[orygunhiker]

I don't have direct knowledge on how other GSM carriers handle your phone configuration with a local region SIM card, or why it would have anything to do with your contacts, but I do know that it matters that you had your phone unlocked before going and I am guessing that having to dial international may indicate that it is being routed back thru T-Mobile in the US, which would also mean you are getting charged the international rate per minute. If you did have T-Mobile unlock it a few weeks before traveling there, maybe contacting cust support or thru online methods will help get that resolved. Best of luck to you.