Default [Q] my htc one x unlock code dont work

hi,i recently got an htc one x off ebay. it came with an unlock code but it dont work. thinking the seller gave me the wrong code i tried to unlock it myself and took it to different shops to unlock it and we all got the same code. is it possible that the phone has a wrong imei code? i check the back of the phone there is no imei there, and i check the sim slot and did not find any there either. can someone plz help me