Wow, incredible someone would just do that! Especially after being told you had designed it. The nerve of some people
I'm just curious... did you ever back yourself up with the poor man's copyright (send copy of design to yourself in a sealed, certified envelope and after signing for its receipt, do not open)? You could always just go straight to Library of Congress (
http://www.copyright.gov/) for a legit copyright form (always advised) ...that way there's no question. I always did the poor man's copyright before I did anything --it's the final proof that usually wins in case someone else tried to copyright our works.
I was a publisher for a long time --this might be a slightly different scenario, but often times we accepted use with mention of the designer and a link or contact info. It generated business so it was a win-win
Good luck with that! Let us know how it turns out..
Have a great day
