American Transmissions

My truck was slipping sounded from differential took in in explain the sound said it was my transmission pick it up drive it home it was worse added additional problems vibration shifter is hard still sliping exhaust leak I've taken it total of 5 times still can't get it now he wants to charge for my differential.he didn't even take the time to inspect it first to make sure it wasn't something else and there's more but honestly make me sick thinking or fitting everything on here am in the processes of Filing a complaint to BBB and then court