This is why you buy your phones unlocked and unbranded for full price. (or at least flash to an unbranded ROM - however it could cause some complications) You could probably save money too in the long run with prepaid MVNOs.
Get used to it, but hey, at least AT&T hasn't reached the level of delay it gave Windows Phone 8.0 GDR2 + Lumia Amber for the 820 and 920.