Had the exact same issue with a front ABS sensor from a motor factors selling on ebay. They had it listed as the correct part number and picture, but in the listing had it as the wrong side (I didn't notice). It turned up wrong, so I messaged them and pointed it out, and they corrected the listing and arranged collection of the wrong part when delivering the correct one next day. Apologised profusely, and no hassles at all.
In the UK, rear right is the drivers side to both VW, VCDS, and should also be for motor factors.