network carrier trouble on iphone 2G
I own an iphone 2G more than 18 month, and I had no any problems, but after updating to 3.0 I got the following situation: I was visiting a different country and I used Ipone in roaming. After returning in my home country I was not able to get my carrier back. Iphone remain stuck up in roaming. I reinstall the OS than everything works well for a while, tahn angain I was visiting a different country and that carrier name was the same name with my countru carrier. Now I can't send any SMS, I can't make any phone call, and when somebody else calling me, if I'd answer is going to charge me a lot of money. Can somebody help me with any advice?
thanks in advance for any answer