If you have booked an offer with all the necessary insurances and no excess via billiger-mietwagen.de, there is no need for supplementary rental car insurance on site.
Unfortunately, some rental companies still keep trying to sell what are actually unnecessary insurances to customers. Do not allow yourself to be pressured into taking out insurance, but show your voucher on site, which lists all booked services and insurances for the rental car.
If you need help with a pushy rental company, contact our customer service as early as possible.