Bought in Ebay in 2014. I can’t find the receipts anymore. Somehow the sector is not mature yet and companies and products come and go and after a few years you can’t get spare parts anymore.
The battery broke. Unfixable. I contacted the German manufacturer of it and they said there is no way to replace the three broken cells. There is also no new replacement battery pack on stock anymore. The BMS was built into the battery pack, as usual. The Controller for the motor was integrated into the battery holder. So I had to replace the controller, and with it the display too, and get a new battery. The only part I could carry over was the motor.