Pegasus Airlines Lost My Bag After Forcing Me to Check In Carry On

I had a very bad experience with Pegasus Airlines. I was flying from Tbilisi to Berlin via Istanbul, and they forced me to check in both my carry-on bags, saying the flight was crowded. When I arrived home, one of my bags did not arrive. I opened a case at the Lost and Found office in Berlin Airport, and they gave me a number to track it on Pegasus Flybot, which is the only way to communicate with them. However, when I tried, the Flybot did not recognize the case number, so I opened another case under my name and contact information online. They said they would contact me within 96 hours to inform me of the baggage location and the expected delivery time, but 12 days have passed and no one has contacted me. Every time I try to track the case, it still says “in review,” which clearly means they lost it. I need help to recover the cost of what was inside my bag, and I do not know what to do next since there is no human to speak with.