You are not allowed to name and shame on the forums.
First of all, file a complaint via the Xbox, the XBL PET will investigate it and take appropriate action. Then block communications with the user so that he cannot send you any more messages. Do not send him any messages as that will unblock him.
Finally avoid him as a player so that you are not matched up with him in the future.
I would say this is some one trying too scam points out of people because I believe there is still no hack been made as of yet for black ops. Well I frequent the black ops forums and am led to believe this is still not possible