Not necessarily that the guy did something malicious, but he could be making it exceedingly difficult for amazon to solve his problem. It seems like such a simple solution to me - if the account is for some reason not unlockable, create a new account, gift credit the guy all his purchases, and permanently close the old account. I know that the CSRs have the ability to do this. If they aren't, there's a reason.

Initial guess, from some experiences with chargeback happy customers, is that the guy started initiating chargebacks before giving amazon a chance to resolve his problems, and amazon is refusing to help him until he cancels the chargeback process.