Is the replacement value too low after a collision?

Hello, two weeks ago someone drove on our Ford Focus Ghia Kombi (137t km on the speedometer, 115hp, 1.8l) from 1999. Unfortunately, he hit the tow hook and pushed the right back so 0.5cm forward. Then goods at Ford and they ordered a DEKRA expert. He had looked at the car and submitted an expert report. This then said that the car has a replacement value of 3100€ and a residual value of 500€. Reperaturko Unfortunately, we only had the crossbars on the rear axle and the handlebar rubbers exchanged for almost 1000€ in January, because the car was still really top, had a great equipment, was able to drive and my parents wanted to drive it for a few more years. Now, of course, you can get a new Ford Focus on the used car market for the 3100€ with a little luck. that the rubber bearings on lateral and longitudinal handlebars have not yet been made there and that there will again be similar costs to us in the next years as before.. Does it make sense to go to the lawyer now, because maybe because of this fact more money is to be made out? Is already annoying.. Hope you can help me a little bit and maybe give us further tips, what we should consider when handling the damage regulation, so that wi Don’t give away money. Greetings, Patrick