signal problems - always searching for network

[Guest The Godfather]

I've bought a PDA from Dubai a couple of months ago called Xtel ONE (WM5, 520MHz) and it was very good but within the last week or so, I have been experiencing call drops and alot of lost signal problems. I have never had poblems until recently. It had been dropping probably 75% of my calls and spends most of the day with "no service" because it cant seem to find a signal.

Any ideas on what the problem is or what I should do ?

P.S: I've made a hard-reset though...

Thanks In Advanced...