Hey,

Are you able to pull the battery, put it back in, then turn it on?

How about trying to get into the recovery menu. You do it by....

Pulling the battery and reinserting it after 10seconds. Then you need to hold down the UP-DOWN-MIDDLE Volume buttons (yes the middle is a button), and the power button at the same time.

If that brings you to a recovery menu, you can fix it by flashing to a stock or custom rom. If not, you may need to check out alternative ways to get into the recovery menu.

If none of the ways to get into recovery work, try buying or making a 308ohm Jig. You can find Youtube or web posts on how to make it (or buy them on ebay for like $6). The JIG should bring you into download mode, which also lets you flash your phone with a ROM.

Anyway, let us know.

 

When plugging the phone into an outlet, does the battery charging screen come up? If so your still in luck.
And yes, a jig is you're best friend. AT&T just wants your money, they don't wanna help.

 

If the charging screen doesn't come on, you may very well be hard bricked. But the jig is definitely worth a shot, just try it as a last resort.