Damage control in case of reparated (!) damage

Hello, yesterday on the highway a bigger Mercedes drove to the VW Golf of my friend EZ 10/2008. Guilt question clearly, the damage is also relatively large, because the body is definitely warped. e.g. the rear lights look out of the body now by 0.5cm. This is the second accident of this kind, at the first the vehicle was towed into a VW car house and repaired there. I was transferred a depreciation of 1,300€. At yesterday’s time the car was was previously optically 100% impeccable, for which I also have a witness, because the car stood for sale and an hour before was an interested person there, who confirmed to me the freedom of objection of the vehicle (had indicated the repaired pre-damage nat. at the sale). The buyer found zero bumps, scratches or similar. Had before the sale also asked again with reference to the pre-damage at a Karrossiebauer, who praised the “perfect work” of the car dealership. I have to admit that I didn’t expect it because the question of guilt and the freedom of objection of the vehicle was actually given to me. Can someone help me what I have to pay attention to? I want to wait for the report and then decide what happens to the vehicle, but I don’t want to fall into a trap. Thanks to the fact that the report is quite simple, but today the expert has experienced a bad surprise. e and lg