I bought a nokia 5330 xpressmusic last week from Ebay which was originally on “3” 3G network but unlocked. I’m on Vodafone and the phone worked fine for a week, displaying most of the times the “3G” sign. Now when the phone is working on 3G I can’t receive calls, whereas when it’s on GSM, its fine, so I presume I have to make the phone only work on GSM. The menu option “network mode” is not existent in my phone settings menu. Help me.