diff --git a/account_bank_statement_import_online_ponto/models/online_bank_statement_provider_ponto.py b/account_bank_statement_import_online_ponto/models/online_bank_statement_provider_ponto.py
index 355de12..28658fe 100644
--- a/account_bank_statement_import_online_ponto/models/online_bank_statement_provider_ponto.py
+++ b/account_bank_statement_import_online_ponto/models/online_bank_statement_provider_ponto.py
@@ -99,9 +99,7 @@ class OnlineBankStatementProviderPonto(models.Model):
                 sequence
             )
             new_transactions.append(vals_line)
-        if new_transactions:
-            return new_transactions, {}
-        return
+        return new_transactions, {}
 
     def _ponto_get_transaction_vals(self, transaction, sequence):
         """Translate information from Ponto to statement line vals."""
diff --git a/account_bank_statement_import_online_ponto/models/ponto_interface.py b/account_bank_statement_import_online_ponto/models/ponto_interface.py
index c84626c..d9f0c70 100644
--- a/account_bank_statement_import_online_ponto/models/ponto_interface.py
+++ b/account_bank_statement_import_online_ponto/models/ponto_interface.py
@@ -105,37 +105,45 @@ class PontoInterface(models.AbstractModel):
         if response.status_code == 400:
             # Probably synchronization recently done already.
             _logger.debug(
-                _("Syncronization request rejected: %s"),
+                _("Synchronization request rejected: %s"),
                 response.text
             )
             return
         data = self._get_response_data(response)
         sync_id = data.get("attributes", {}).get("resourceId", False)
-        # Check synchronisation
         if not sync_id:
-            return
+            raise UserError(
+                _("Ponto : no resourceId in synchronization data %s") % data
+            )
         # Poll synchronization during 400 seconds for completion.
         url = PONTO_ENDPOINT + "/synchronizations/" + sync_id
         number = 0
-        while number <= 10:
+        while number < 10:
             number += 1
-            response = requests.get(url, headers=self._get_request_headers(access_data))
-            if response.status_code == 200:
-                data = json.loads(response.text)
-                status = data.get("status", {})
-                if status in ("success", "error"):
-                    if status == "error":
-                        _logger.debug(
-                            _("Syncronization was succesfully completed")
-                        )
-                    else:
-                        _logger.debug(
-                            _("Syncronization had an error: %s"),
-                            response.text
-                        )
-                    return
+            if self._synchronization_done(access_data, url):
+                break
             time.sleep(40)
 
+    def _synchronization_done(self, access_data, url):
+        """Check wether requested synchronization done."""
+        response = requests.get(url, headers=self._get_request_headers(access_data))
+        if response.status_code != 200:
+            return False
+        data = json.loads(response.text)
+        status = data.get("status", {})
+        if status not in ("success", "error"):
+            return False
+        if status == "error":
+            _logger.debug(
+                _("Synchronization was succesfully completed")
+            )
+        else:
+            _logger.debug(
+                _("Synchronization had an error: %s"),
+                response.text
+            )
+        return True
+
     def _get_transactions(self, access_data, last_identifier):
         """Get transactions from ponto, using last_identifier as pointer.
 
diff --git a/account_bank_statement_import_online_ponto/tests/test_account_statement_import_online_ponto.py b/account_bank_statement_import_online_ponto/tests/test_account_statement_import_online_ponto.py
index d27893c..3f66213 100644
--- a/account_bank_statement_import_online_ponto/tests/test_account_statement_import_online_ponto.py
+++ b/account_bank_statement_import_online_ponto/tests/test_account_statement_import_online_ponto.py
@@ -229,17 +229,28 @@ class TestBankAccountStatementImportOnlinePonto(common.TransactionCase):
 
     def test_ponto_buffer_purge(self):
         """Create some old buffer records and test purging them."""
+        buffer_model = self.env["ponto.buffer"]
+        buffer_model.sudo()._store_transactions(self.provider, THREE_TRANSACTIONS)
+        # As all transactions have a different date, they will be in separate buffers.
+        buffers = buffer_model.search([("provider_id", "=", self.provider.id)])
+        self.assertEqual(len(buffers), 3)
+        # Non ponto providers should not affect buffers.
+        self._expect_purge_result(service="dummy", retain_days=15, expected_length=3)
+        # If retain date not filled, buffers should not be purged.
+        self._expect_purge_result(expected_length=3)
+        # If retain date filled, buffers should be purged.
+        self._expect_purge_result(retain_days=15)
+
+    def _expect_purge_result(self, service="ponto", retain_days=0, expected_length=0):
+        """Check result for purge in different scenario's."""
+        buffer_model = self.env["ponto.buffer"]
         self.provider.write(
             {
-                "ponto_buffer_retain_days": 31,
                 "active": True,
+                "ponto_buffer_retain_days": retain_days,
+                "service": service,
             }
         )
-        buffer_model = self.env["ponto.buffer"]
-        buffer_model.sudo()._store_transactions(self.provider, THREE_TRANSACTIONS)
-        buffers = buffer_model.search([("provider_id", "=", self.provider.id)])
-        # As all transactions have a different date, they will be in separate buffers.
-        self.assertEqual(len(buffers), 3)
         self.provider._ponto_buffer_purge()
         buffers = buffer_model.search([("provider_id", "=", self.provider.id)])
-        self.assertFalse(bool(buffers))
+        self.assertEqual(len(buffers), expected_length)
diff --git a/account_bank_statement_import_online_ponto/tests/test_ponto_interface.py b/account_bank_statement_import_online_ponto/tests/test_ponto_interface.py
index 17bcf66..d56a6ca 100644
--- a/account_bank_statement_import_online_ponto/tests/test_ponto_interface.py
+++ b/account_bank_statement_import_online_ponto/tests/test_ponto_interface.py
@@ -91,6 +91,32 @@ class TestPontoInterface(common.TransactionCase):
         interface_model = self.env["ponto.interface"]
         interface_model._ponto_synchronisation(access_data)
 
+    @patch("requests.get")
+    def test_synchronization_done(self, requests_get):
+        """Test getting account data for Ponto access."""
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_response.text = json.dumps({"status": "success"})
+        requests_get.return_value = mock_response
+        # Succesfull sync.
+        self._check_synchronization_done(True)
+        # Error in sync.
+        mock_response.text = json.dumps({"status": "error"})
+        self._check_synchronization_done(True)
+        # Unexpected error in sync.
+        mock_response.status_code = 404
+        self._check_synchronization_done(False)
+
+    def _check_synchronization_done(self, expected_result):
+        """Check result for synchronization with current mock."""
+        interface_model = self.env["ponto.interface"]
+        access_data = self._get_access_dict()
+        synchronization_done = interface_model._synchronization_done(
+            access_data,
+            "https//does.not.matter.com/synchronization"
+        )
+        self.assertEqual(synchronization_done, expected_result)
+
     @patch("requests.get")
     def test_get_transactions(self, requests_get):
         """Test getting transactions from Ponto."""