The problem is, your phone is being locked by those who sold you the phone , I have gone throught the same problem before, I had to send my phone back to Hong Kong and asked those stupid people to unlock it for me because noone was able to unlock it for me in New York.What a shame!
Why don't you bring your phone to Chinatown and try to get someone to help you, I know such a guy owns a cell phone company in Chinatown, if you need the address,I'll be more than happy to give you his number, maybe he can help you.
hi... ur P320 is bought from HK, there is no problem to work in USA. However, there are only 2 communication companies can be used as GSM, they are T-mobile and AT&T. another companies SIM cards are CDMA or other format, u cannot use.
my nokia 8800 can automatically search the network from T-mobile after putting the SIM card, it works. so I think the problem is u are using the wrong SIM card. hope it can help.