said by Jim Gurd :

Did you add a new line? If so that's why. I'm talking about simply increasing or decreasing your monthly minutes.

said by hhawkman :

So why should adding a new line increase the contract on existing lines and phones? This happened to me when I was with AT&T. We got a new phone and line for our stepdaughter. Separate billing. Separate account. The current plan they were offering was a little better minute-wise than our existing plan (not by much, and same price), so we changed to the new plan (no mention of any contract extensions). A year later when our contract was supposed to end and we tried the cancel the 2 old lines, we were told we had another year on our contract, and would have to pay a "termination fee". We took it all the way to the FTC, and didn't have to pay. Then we kissed AT&T and their crappy 2 year old phones goodbye.

said by cyrus369 :

Sounds fishy to me, did you do this over the phone, in a at&t corporate store or through a mall store? Each line has its own separate contract, when you add a line or extend a contract on one line it does NOT change contracts on any other line. And when you change your plan it does not extend your contract, I do it all day long and have yet to see it change a contract date...