I can't give any advice about searching Macs - I don't go there; but I will point out that anyone who got your credit card number could probably get your (or his) email address, and it's apparently pretty easy to "fake" a return email address. Virtually all of the "spam" I get (on a Hotmail addy) has false returns, and I wouldn't expect a porn site to be too fussy about checking.

Since they put his email addy with your card number, it's likely(?) that he may have used them together (maybe even inadvertently) - but it would only take one use on an insecure or dishonest link to expose it to use by someone else.

John