If the value of car repair is estimated by the insurance company to be higher than what was estimated by the workshops, is there any problem with that? Is it permissible to negotiate with the insurance company if its estimate is lower than the actual repair cost? Is it permissible to accept 20 dinars as compensation for damage? Is it permissible to repair the car for less than the amount received from the insurance company?

There is no objection to taking the compensation estimated by the insurance company for the damage sustained by the car. It is not obligatory to spend all of it on repairing the car. Rather, it is permissible to take it even if the car is not repaired, because it is compensation for existing damage. The insurance company did not authorize you to carry out the repairs; rather, it estimated the damage and offered compensation for it. Therefore, it is permissible to accept the amount and benefit from it, whether the repair cost less or more than the compensation.