What should i do?

[boneskid1]

Alright so i have bought a used htc evo 4g to use as a media device. the phone i picked up has a bad esn but that didnt bother me to much since i will be using it off of wi-fi anyways. but i have run into a problem.......... when i plug in a headphone jack sound only comes out of the left side of anything plugged in. if i slightly pull the plug out it plays out of both sides, and it the plug is all the way in and i move it back (the screen is facing me) it sometimes works. So my question is........ How should i go about repairing it? should i disassemble it my self and try to fix it or send it in to htc and have them do it? yes the warranty is up for sure.

If someone could help it would be great as i am in a grey area right now with what to do.