There was a double charge issue. I had already paid in full on the rental website, but was charged an additional £250 rental fee and £252 deposit for damages when picking up the car. I told them I had already paid to the rental company, and they said it was a deposit. My understanding was that the deposit would be refunded upon returning the car. I contacted the rental company, and customer service assured me it was a pre-authorization and I should just pick up the car. Upon return, the damage deposit was refunded, but the £250 rental fee was not. The car company said the rental company would refund me. I called the rental company to report the issue, and the customer service mentioned they would handle it after the New Year holiday. Needing to catch a flight, I returned the car and left. Now 10 days have passed, and the car company is still verifying the issue. It seems the process in the UK is quite slow.