It's not a scam in the true sense of the word, but nevertheless still very annoying.
There's not a lot you can do about it though.
"I bid on an item and won only for the seller to cancel my bid and relist the item immediately"
Do you mean the seller cancelled your bid first then ended the listing or do you mean it finished with
you as the winner but the seller cancelled the transaction ?
I sometimes feel sorry for new, inexperienced sellers who start an auction price too low and the item sells
for very little but if that same seller knows how to cancel the transaction using a reason that's not true and
benefits them, so they don't receive a defect, I'd have no hesitation in reporting the seller.
