Built to fail
Why can't automakers do a better job on modularization? It shouldn't be an AT&T system. It should be a standard USB jack where you plug in a standard USB cellular radio. These systems become deadweight when the trial expires because they don't work the way people want and they can't be upgraded. If the cellular system is integrated anything like Audi's "sounds like a small AM radio" Bose system, replacement is best accomplished by getting a different brand of car.