Unit-linked life insurance HDI buyback?

Hello everyone, I hope I can get some help here and shed some light on my situation. When I was born, before the turn of the millennium, my parents took out unit-linked life insurance for me. This old contract is currently with HDI Leben. Since the beginning, €25 (initially in DM) has been paid into the insurance every month. After several months of correspondence, many hours on hold and countless emails