Do you mean the seller is telling you that the item is broken and he is reluctant to ship you an unsatisfactory item?
Ask him to send you a Mutual Cancellation through the Resolution Centre.
If you have paid, do not agree until he has refunded you.
If he does not refund promptly, refuse the MC.
Do you mean the seller is telling you that your Paypal payment did not go through?
Ask him to confirm his Paypal address (it's an email address and nothing he should be afraid of.)
Do that address and the address you paid to match? If so, he should be able to collect his money.
Is this a new seller? Or does the seller have poor feedback?
Anything under 10 feedback (and as likely 50, if he sells cheap items) for selling is a new seller. His feedback as a buyer is irrelevant.
Are his Detailed Seller Ratings under 4.5? There are a lot of complaints about his selling and he may be restricted.
Is his feedback rating under 98%.?There are a lot of complaints about his selling and he may be restricted.
With any of the above, Paypal may be Holding your cleared payment for up to 21 Days. However, the seller is still required to ship within seven days.
Did you pay through Paypal from your bank account? It can take up to 10 days for an e-cheque to clear, during which time the seller cannot print your shipping label.
So some of these problems are scams. Some are misunderstandings by the seller.
Contact him and ask what the exact problem is and let us know. We can give better advice if we understand the question.