Speak to your bank and as [superchroma] has suggested cancel your credit card and fully aprise your bank of what has happened.

Document everything, get all documents certified by a court or JP (if that is available in your particular area) and then send it via certified main to yourself for a permanent record and if they decide at some time in the future to be naughty then you have at least an official record that could be submitted in evidence in any applicable matters.

Such processes can be useful, especially any officially recognised documents.

Finally, avoid doing business with them in every way and avoid doing business with every company or vendor who only uses PayPal and let that company or vendor know why.

You may be small fry in a big ocean, but even small fry (if enough are involved) can cause big problems with the big fish.