Unauthorized €500 Mail Order Charge by Flex To Go and Rentalcars in Germany

I rented a vehicle between June 11–14, 2026, from Flex To Go near Düsseldorf Airport, Germany, through Rentalcars.com. To prevent any deposit deductions from my card, I paid an additional €90 for a full protection package on top of the rental fee. I explicitly stated that I would use the vehicle exclusively within Germany, and the booking was completed accordingly.

An additional €100 fee was requested for cross-border driving outside Germany, which I declined, reiterating that I would not leave the country. During the rental period, I drove from one German city to Aachen, and then to Monschau—which is also located within Germany—using German roads. Along the route, there were no warning signs indicating a border crossing, nor did the navigation system issue any alert regarding border entry. I later learned that a very short stretch of the road passes through Belgium; however, I encountered no visual or digital warnings while driving and had absolutely no intention of exiting Germany.

Four days after returning the vehicle in perfect condition and arriving back in my home country, I discovered that €500 was charged to my credit card via mail order without my knowledge or consent. Following this transaction, an email containing an invoice was sent to me, but because the invoice file was password-protected, I cannot open or view the document to verify the grounds for this charge. This practice lacks transparency and constitutes an unauthorized transaction.

I submitted written objections and formal complaints regarding this incident to both Flex To Go and Rentalcars.com, but I have received no response to date. Neither the justification for the €500 deduction nor the reason why this amount was collected despite my purchase of a full protection package has been clarified.

I demand the immediate cancellation and full refund of the unauthorized €500 charged to my card, a clear and comprehensive written explanation regarding why this deduction was executed despite purchasing a full protection package, and the immediate resolution of my grievance.