Insurance doesn’t want to replace Navi, what to do?

Hello community, a friend recommended this forum to me, because you would always get competent answers here – so I just try it and turn to you with a problem, which really bothers me at the moment… A few weeks ago my Audi was broken up in an underground garage – the Navi was stolen. Only the strippings hang where the Navi was before (Audi Navi plus). Other things were not stolen. Burglary tracks not visible! Advertisement made to the police – Police officer looked at the car, no burglary tracks – however (O-Ton): nowadays totally usual. Notification of the damage case with the insurance on the same evening: Statement there that everything was no problem, I should contact the Select workshop. Said, done. The workshop manager photographed everything and gave his estimate to the insurance. Some time later a reviewer of the Dekra called, he wanted to check my car for burglary tracks on behalf of the insurance company He came, he documented everything, no traces of burglary (also here: totally usual nowadays). Now came the report of the insurance: because no traces of burglary exist, nothing is paid at all. Previously there was always talk of time value (always). What do? According to Google there were some cases, where insurances had to pay after all and also not only time value, but new price, because no used market for Navis is there (no serious one). I haven’t heard that yet and according to my documents, a Navi is also listed in the terms of the contract under the insured parts. Who can give me advice on what to do? Do you have any chances in a lawsuit? I’ve been insured there with two cars and various other insurance companies and never had any damage. And now this… I would like to thank you in advance for your help! Greeting, Jürgen