[Oxymoron238]

Did they check your phone, or just the battery? The battery isn't the problem; it's the phone (or at least it was in my case).

Have them look at the phone. When I went up there, I told them that I tried three different batteries (stock, mugen, and seidio), and none of them could get my battery to last the whole day.

Just be sure to tell them that the phone is the problem, not the battery.