What actions are possible against somebody reselling my products without permission?

I've just been informed that somebody called Person-I'd-Dearly-Love-To-Name-In-This-Forum-But-Can't-Because-of-the-Terms-of-Service has been reselling the gift version of my STARLABS Anti-Idler gadget without my permission.

First, I'd like to ask if there's anything I can do about this (in the event that he doesn't stop when I ask him nicely).

Second, I'd like to warn anyone off of buying this device from anyone other than one of my STARLABS vendors in-world, because he's picking my pocket.

If you feel that someone took advantage of the permissions bug that was introduced into the code Sunday evening (and locked down Sunday night) and is selling copies of something you made without your permission, please file an abuse report. We’ll follow up with the buyer and sort out the IP rights. Also, please read Robin's Blog about this topic.