Broken button problem


Hi everyone,

I have had my xperia mini pro for a good 2 months and just recently the volume button seems to have broken itself, The Volume up button Has jammed itself in, I wasn't able to do anything with the button and it wouldn't alter the volume, now it has jammed in and turns the volume up by itself and i can hear it beeping away to itself whenever it turns it up and i can't turn it down it will just turn itself back up, the phone is genuine and was brought from a proper store brand new and is in warranty.

I am wondering if anybody else has experienced the same fault with this phone, and what can i do to fix it ?