I tried unlocking my nokia lumia 900 with a code that At&t gave me and it doesn't work, now I have no more attepts. is there anyway I can unlock my phone now?
You probably need to contact ATT and tell them the code they provided does not work.
Also, may I suggest editing your title to provide a little more detail? i.e., "Unlock code issue" or "Unlock code doesn't work." Those of us who browse the forums thrive on more information.