Is that while wearing gold chains, a bandana and threatening to "bust a cap in their ass"?
I had a similar experience when I bought Half Life 2. Got it from Sainsburys and went to register, said it was already registered. I had to get in contact with the company, and provide a photograph of the CD and case with the serial number clearly visable, proof of purchase and ID, then they unlocked the serial number for me however it took a good few weeks for them to do it.