Saw some guy sell your Design printed on ebay . Or maybe its you .
It's not me, and it seems it's not my design, but in fact I've released it under the MIT License, which permits all uses and reuses, including commercial, provided there is attribution. As long as a seller provides that attribution -- preferably a link to the Github repo so people know there are other ways to get the item -- they are free to sell it on eBay or anywhere else and that's cool.