k800i problem

Cud anyone help. I've got a sony ericson k800i but have started to get problems with the external speaker when playing mp3's with the volume being extremely low (even on max volume) and the headphone aren't working anymore, Ive bought a new pair and they are the same.
Has anyone had the same prob and know how to fix it.

ALL k800's i known of have fu***** up, mine lasted 2 weeks, cam fu**** up, kept turnin itself off, etc, AND all 9 other people who i know who have had one ( had, because they got rid of theirs too) it messed up on them too, my advice is to go back to shop and get a full refund, your statutory rights say that that phone should last a year at least, i think, maybe its 2 years, i cant remember, meh