If warm soapy water doesn't get it off, then other things won't, or they would straight up damage the PVC.
Make-up remover is quite hard on PVC, I wouldn't be surprised if the treatment would be followed by peeling soon.
If you wouldn't have used that on the bag, I'd say return, but now I don't feel I can say that. They didn't specify the stain, that was not nice, but they also wouldn't get the same bag back. It's a tough one.