I get that this is bad form, but people are totally overreacting in here. This isn't 'disgusting' or 'scum bag' or anything like that. It's an issue, sure, but nobody is being 'shady'.
Removing copyrighted material when found is pretty standard. In fact, it's their -only- recourse when someone violates a copyright. This happens anywhere people can create content, and as long as the company removes it when flagged, they're generally in the right. Most likely their terms say you can't -buy- OR -sell- copyrighted, vulgar, or racist material. [and for good reason, discussed later]
Now you ask, why don't they give a full refund? Because if they didn't 'punish' both buyers -and- sellers, then people could just keep reposting copyrighted material and OP can just keep buying it, getting full refunds as soon as it's removed and then just buy the next copy put up. Full refunds not just allow, but encourage, copyrighted material. So they don't do full refunds, but if someone asks, they try to 'make it right'. I realize this isn't perfect, and OP is out money... but if you look at it from their perspective, it makes a bit more sense -why- it happens this way.
They should probably give a full refund for the first violation, and then never again. That would be a better solution. Though in this case, they did sort of try to do that, by giving 10k, which covers one violation with a nice bonus for your trouble. The problem is, in this case, the OP bought over 10 things that violated copyright. So it's a kind of rare case. They probably should have covered that whole amount and been done with it, and then said 'never again'. But it's hardly 'scumbag' behavior.