N82 (Chinese) problem. Help ME!!!!!!

I've got Nokia N82 on ebay(one week old). Turned out it's a chinese version(not a fake though). It seems to have many problems.

First of all, it keeps losing signals and says "no service" and back on where as my another phone has full bars all the time with the same career(t-mobile) I've set "select network" as automatic.

I tried to restore back to factory setting using the option on the phone. But I do not know the password(12345 doesn't work either). then I tried hard resetting by pressing *#7370# + send, but it just says "not done"

I'm really stressed out about this phone. and I can't return it to the seller now.

Please help me.

I don't understand...chinese but not fake?

Sounds like you may have a bad phone, you could always call Nokia to see if they can troubleshoot, otherwise if it is a "real" Nokia phone, you can find someone (online) to re-flash your phones firmware.