That sounds... odd. They don't reprogram it?

What AT&T Breakup? Explain.

Malte Ubl T-Mobile and AT&T were supposed to merge in the anti-consumer ecstasy to make largest US-wide GSM carrier. Alas the deal was not allowed by the regulators, and in initial offer AT&T had "break-up" clause that gave T-Mobile some spectrum, cash and roaming agreement (was supposed to be used to prop up regulators to approve the deal "otherwise we lose soooo much" type of thing I guess) 

Max Smolev Ha, I was hoping it was something like that. May apply for me, too. My SIM is from January I think.

Mine was so old that it was failing to register on the network, so hard to say what constitutes "old". I'd ask at the store though, the folks on the phone really didn't know about this.

Paul Lindner Yeah this sounds more like "worn out" or "bad contacts" or whatever. If it fails to register t-mobile used to give you a new one for free at the store (well, they'd charge for it and apply credit immediately). I don't think the "new" frequencies that are being transferred from ATT to T-Mobile will make any difference for a while as they'd have to actually deploy hardware first :)

I myself use Straight Talk (AT&T without the LTE part) so I don't deal with t-mobile that much lately (though might switch to Straight Talk T-Mobile sim if ATT data woes drive me mad)