Maybe check with Paypal why the seller can't accept, might have a bad history. If they stated that they accept PayPal and can't won't I would contact Ebay and let them know what is happening, it's likely a scam. I'd expect that they would step in and expect you can cancel order under the circumstance but make sure you alert Ebay first.
I wouldn't pay by check for anything here, some credit cards have purchase protection but even that might not save your butt here depending on type of purchase and Card limitation, even Paypal has had bad history in customer protection (not getting back all of purchase amount) with people saying use Credit card through Paypal as a double buffer protection.
