Residual value buyer offers less because of intermediate mileage

Hello, I have the problem that after an accident that was clearly not indebted by me, my car represents an economic total damage. Because of this I decided to reject the vehicle and invest the replacement value in another car. My damage report showed a residual value of 2300 euros. the opposing insurance, however, has found another offerer via an online exchange, which offered 2600 euros. Ergo have the a lower RE So far not bad… Now I wanted to deal the deal, the buyer is no longer willing to pay the amount of 2600 €, because the car has in the meantime driven etlcihe kilometers. I give to 150 kilometers a day are not little… the whole thing is now going on for 4 weeks, i.e. the box certainly has 300 kilometers more on the speedometer at the end. However, here we talk about a vehicle which is now not 150,000 kilometers but 152XXX km d The Kist is still in traffic and that’s why I couldn’t get a rental car!? What now… annoy me that I didn’t sell right after the old report…The lawyer seemed to me too much, but because of the damage situation was probably the best. In the insurance the lady did not know anything about the regulations to which extent the vehicle should have stopped. There was also no hint from the gutachter… Thanks already for helpful hints. Dave