After total damage, insurance pays rental cars only 20 days

I had an accident with my vehicle in August (debt question clarified). My vehicle was declared as total damage by the expert. The amount of damage (approx. 7000 €) was recognized by the opposing insurance immediately in full. I handed the case over to a lawyer for safety and obtained a rental car. So far so good. Unfortunately, the insurance read itself with the payment of the damage sum for no apparent reason over one and a half months. E-mail and Tele The employee only informed me that he had 200 applications on the table and that he would be on the table. In the meantime, I asked my lawyer to clarify an extended rental period. I could not, of course, purchase a vehicle of the same value during the time of the unpaid damage amount (age credit could not be replaced, etc.) and was absolutely dependent on the rental car. After which the damage amount was received I de n rental car delivered on the same day. But now the opposing insurance only wants to pay the well-known 20 days rental period and not the further 25 which would of course have been possible without any problems, the damage amount would have been transferred in due time. Now I feel in the equality before the uninsolved accident considerably injured, because the opposing insurance can of course not explain to me plausible how I would have an equivalent vehicle without payment of the damage amount I hope someone can help me or know a similar case. Thank you in advance.