The European Commission provides a platform for online dispute resolution (OS), which you can find here https://ec.europa.eu/consumers/odr/
We are willing to participate in an out-of-court arbitration procedure before a consumer arbitration board.
The federal universal arbitration board at the Center for Arbitration e.V., Strassburger Straße 8, 77694 Kehl am Rhein, is responsible. https://www.verbraucher-schlichter.de.