I had Cingular for 4 years, decent service (Wash DC area). Moved to Washington State, got a phone from work so I tried to cancel my cingular service. Filled out 3 different forms over a period of 6 months, thought the thing was over. Checked my credit report 6 months later and they had placed a negative rating for failure to pay my bill for the period AFTER I had canceled the service. Took another 2 months and a lot of cussing at the "customer service reps" and their supervisors to correct. Never again.
That's EXACTLY the type of thing I'm talking about. Believe me, most reps were probably on your side, but were not allowed, by management, to just simply take care of it. That's the situation I found myself in time after time after time.