i600 does not work on my 1800 Mhz network ?!?!?

[Guest phat_sua]

Hello guys I have an Italian i600 NoBrand.

I currently live in Romania where we have e providers... Vodafone and Orange for 900 Mhz and Cosmote for 1800 Mhz.. my provider is Cosmote... The problem is that the phone does not work on this Network... I have tried it with vodafone and orange and it works perfectly but when I insert my Cosmote SIM the phone says "No Service". What can I do ... when I search for the network I can find it. Somethimes when I reboot it says Cosmote (however if I call myself from another phone it says my phone is closed) and it goes back to No Service in 3-4 minutes. One when I was in this No Service mode I recived an SMS from a friend.. (OMG how did that get througt .. ) I cannot call anyone or recive any call. My imei is the good one.. its not 0000000000.

Thanks and please help I will be endeted forever..

Also all my FW (PDA . PHONE ..) are i600XXGD12