What is wrong with my samsung captivate?

I just got a samsung captivate and it's really nice but the problem is that for some reason no matter what i do the sound never comes out of the headhones. I tried using the headphones the cellphone came with and I tried using three other pairs of headphones. Is this a hardware or a software problem?What is wrong with my samsung captivate?i believe it's a hardware issue, you have one year warranty on the captivate, call AT%26amp;T.