Automatic Transmission problems of the 1998 BMW 740

Transmission problems - 1998 740il. I bought a cpo BMW 740il with 35,000 miles. Now I have 65,600 miles on the car and I too am having issues with the transmission. While the car was under cpo warranty, I had taken the car to the dealership when I was getting a check trans message, which I have service records for. The dealership refused to acknowledge the error, saying that they could not read the code on the computer. Well now the transmission won\'t go in park or reverse and needs to be replaced and the car is out of cp warranty. Damage resulting = looks like I have to pay $7,000 for a transmission that should have been fixed while still under warranty, as the warranty on the car has expired. The car is not worth more than $12,000 now.