Chevrolet complaint: Radio/ On star

About 7 months ago, my radio went black in my Chevy silverado 2020. The onstar, blue tooth or sirus radio will not work. This may not seem like a big deal, but the dealership would not give me full value for my truck if I traded it back in. The dealership I bought now three vehicles from has changed ownership. My truck has been in for service now 8 different times with nothing resolved. The dealership has changed modules several different times and have given a good effort for the most part in trying to fix this issue. My problem is with Chevrolet. I have purchased chevys practically my entire life and I cant find anyone who can give me an answer about my truck. The latest news is that there are 4 of these particular modules in the United States and no one is willing to sell one. Now GM has to make one and there is no timetable as to when it will be fixed?????? Seriously???? Let me tell GM, well I am not making my truck payment because it isnt working the it is supposed to when I bought it, and there is no timetable when I will send my next payment. This is beyond ridiculous and finding someone who can actually give me answers has been impossible. I just want my truck fixed the way it was when I purchased it.