Registered car sold…

Good evening, as the subject already announced, I sold my car. The whole thing so short-term that I didn’t log it off anymore. Ash on my head.. now it comes as it has to come: the buyer seems to have time to venture around. – or to log off. How should I proceed now? Of course I kept all the data from the buyer in the contract and checked his ID for validity. In advance I was able to find out that it is a dealer who really exists. From the Internet I took this contract: Click The cross I put where it is written: “The insurance is immediately terminated by the buyer. ” Well, it’s only 2 days past but I’m worried what can go wrong. What would you advise me to do? tomas