Running power purchase contract – mileage vehicle deviates. What to do?

Hello dear Motortalk municipality, after mature consideration I decided to buy a VW Arteon. Car is about 1 year old, purchase contract signed at the VW Autohaus on 9.8.18. Car was driven only by the sales manager, one has a good feeling. Running performance lt purchase contract 17,000km. Today then finally the day of collection: – winter bikes are missing (still in a branch…) – Navi SD card is missing – second key is not possible, replacement was still learned today the vert However, the car has run almost 20,400km. For me the maximum of 10,000km/year is a clear difference. Since I have no experience with such situations (like most of them) my question is how to proceed, or what will probably be offered to you. “must” e.g. with a tank voucher or similar? How much € are almost 20% more mileage than agreed with such a relatively new car “value”? Because of the running ability g of course also depends on the return purchase value guaranteed by VW in 3 years I actually do not have a good feeling to solve the problem by “tank voucher” or similar. Should one even insist on undoing the whole business because here a substantial property as the mileage differs substantially? Thank you for your help. Greeting Max