Phone bluetooth not working! Please help?

[Zuby Kiks]

I have bought sony ericsson cedar a few months back, I got a issue regarding the phone bluetooh, I use sony ericsson bluetooh headset mw600,i have been using it for sometime,but recently when I tried to pair up with the phone the bluetooh option in phone stopped working,i can't turn on the bluetooh in the phone anymore it hangs, I did master reset but still the problem persist, I showed the phone to the retail shop from where I bought the phone but they said they can't do anything, now I can't even turn on the bluetooh, please help