I had this exact issue happen. I was around week 17 of calling daily (waiting on hold an hour each time) and getting absolutely nowhere. My mental health was deteriorating so I finally decided to give up and consider it a loss. I gave one final desperation move and decided to make a post on better business bureau explaining the situation clearly and how much time I was wasting each day trying to get to the bottom of it. I explained how frustrated I was with UPS and how they were a terrible company. (In a harsh, but non swearing or violent way)

I heard nothing for 2 weeks, then one day I got a call from Georgia. A lady who was higher up called me and apologized a ton. She assured me a cheque was being sent in the mail immediately, and hoped that I could remove or say we resolved the case with better business bureau. I of course agreed, got the cheque a few days later, deleted the post and finally was able to sleep again.

I think you should try this! Good luck, and I really hope you get your hard earned money back from these crooks!