Rental vehicle purchased, but not wanted

Hello together! The following happened: I looked at a 207 at a car dealer, tested cars and had someone with me who really knew about cars and also looked over it. There was nothing to complain about the vehicle. EZ was 08/07, mileage 22000. However, because I did not want an EX-rental car, we asked the seller and this meant it was not a rental car, but a leasing car. The price fit and I paid the car by cash purchase yesterday. It is now available. still in the car dealership, wg registration, which was not made yet. On the contract “rental vehicle” was ticked, which put me in doubt at first. But everything had to go quickly, the seller made a very honest impression and I explained to myself that leasing is also rent. So I faxed the signed contract the day before yesterday. I know that was absolutely stupid, annoying myself enough! When the letter was picked up yesterday, I saw that as a previous tenant The seller now denies that he has lied to us and does not want to leave me out of the contract, let alone give a discount. I would have bought the car with the knowledge that it is not a rental vehicle for this price. What can you do now? Do I have the right to withdraw from the contract yet? I would like to thank you for (quick) answers. LG