I unlocked a iPhone 3G from ATT with blackra1n and used the phone with a SIM card from A1 in Austria without any problems. But now, a day later, I am in Dubai and when I insert the SIM card from the local phone company Etisalat I can send and receive data, receive text messages and phone calls but I can not make calls or send text messages. When trying to make a call I get a message saying I don't have enough credits to place a call (the SIM card is for a prepaid service and I have enough credits). The same SIM card will work fine on my ordinary Nokia phone. I already reset the network settings on the iPhone twice and a phone companies rep suggested to reset the phone with iTunes (which I have not done yet).
Any suggestions?

Thanks!