Car Sold (replacement dispenser) but buyer does not want/can’t pick up the car.

Moin Moin dear comrades and comrades I sold a Volvo 850 Turbo which was no longer ready to drive about 2 weeks ago (supplementary part dispenser with turbocharger damage and partly removed, logged off). The problem is now the following: Seller has paid the car by bank transfer, so far as is good for paying for his stuff before picking up, therefore a purchase contract does not yet excisate, only the oral as well as written acknowledgment VIA Whatsapp and Facebook. Ebenlich the problem that he A: No time has to pick up the car or B: No more desire for the car. I have now set him a deadline of 4 weeks to pick up (15.12.2015 to 3 p.m.) that the car comes out of the garage here (for which We pay 100€ per month), and raise per week 20€ stand fee since this week. What can I do in case of a car, if he has still not picked up the car after the deadline had ebend a few infos about this.