Thanks to all of my fellow artists and friends for your concern about this all-too-common issue that could affect any one of us.
EmptyEasel.com has a couple articles about copyright infringement. Click here to read them.
I have found out the iOffer is a site similar to eBay. Sellers can set up a "store" to sell things. When I contacted them about this issue, to their credit, they removed the listing.
However, the individual store owner, identified only as hnzp197738, still has my painting for sale. I've sent him/her a message the he/she is infringing on copyrighted material and to remove it immediately.
I think it is incredible that the painting is listed as a "hand painted original." Totally bogus!!! I think they make a print of a painting, and then paint over it with clear gel so it looks like brushstrokes to the untrained, half blind eye. Or, they have factory artists, typically in China, add some paint on top of the print. Even I could not paint such an exact match again without a print underneath.