Insurance does not pay expert opinions and damage

Hello, currently have the following problem: With me someone drove on straight track into the side wall. If then to the right, the police informed, the damage was written down on the accident card again and confirmed by the causer with signature. Also I took some pictures of both vehicles. On the pictures are the damage, the registration plate, the causer and the color of the vehicle from the causer on my vehicle etc. So very clearly actually. Later, then, have an expert report sent to the opposing insurance company. For months no reaction and now the answer that you want to do a follow-up inspection. Neither the damage nor the expert report would be paid until then. Have a lawyer commissioned, who wrote to the insurance company, to pay the whole thing now finally. How can I proceed here? The expert report must be paid after all? Or should I pay the expert report myself and the Versic In order not to have exactly such a problem, I took X pictures, had everything confirmed and still something like that. I could vomit.