I am not an attorney, but I do have a business seller account that I do not use anymore. I will just say this I think your payment is being held up during the verification process of the seller's business accounts.
If the money is "unclaimed" it's not even getting into the other person's account so you can't complain to Mr. X because in reality he probably hasn't got your money yet either. It's being held up by PayPal themselves.. You can't dispute with him because again he hasn't received the paypal money for one reason or another.
Paypal has a phone number that you can actually call on the phone and talk to them. I recommend that you actually call paypal on the phone and ask them where your money is...
