I don't own vB license anymore, so I'm not sure what payment processors they are offering at the moment. But as far as I remember, they don't store CC details on their records, so I'm not sure if there's anything more to lose from your end. Other than the fact license may have been stolen by some crook, who could use it on his pirated forum, I don't see any other compromise. The only other suggestion which I could offer is.. change your server logins and admin account logins of your vB forum, in case you have shared the details on the tickets for any kind of assistance or anything.