You've got some nice copywrite there if that image is yours. Are you willing to give out some vouch copies so you can verify your services? Or use escrow in some way? I know escrow is hard with cultivatable codes, but you can get a trusted member to hold costumer funds before you send the code so you'll receive them once the code has been activated (or something like that).
Yes the design is mine, I paid for it. I could give out some vouch copies, but people would most likely just ask for a copy and then not buy anything, losing me money. I would be happy to use a middle man for a transaction, if you point me to someone that would be nice.