There might be a different way to approach this. You could email him/her and suggest that they a) give you a link as homage to you since they found your design to be so superior as to copy it. Imitation is the greatest form of a compliment. B) find out if he/she will signup under you using your codes so that you will get some credit if he/she does well also since they are using your design. Maybe this approach will give you more satisfaction, and end up compensating you
Tim