I can appreciate your concern, and I’m sure you want to get this resolved, but to use an analogy… if somebody steals your credit card and uses it to buy something in a shop, you need to speak to your bank. They will cancel your card, investigate and do what they can to get the money back in your account. There’s not that much the shop can do.
The best course of action to get this resolved as quickly as possible, is to speak to Paypal.