There is a Contact Seller button on the listing.
Your concern is that the seller may not understand your request.
Two suggestions:
1) Look on your Paypal account and see if there is an open invoice there.
2) Go to Google Translate and enter : Please send me a new invoice for eBay # XXXXXXXXXXXX. in whatever you believe is their language AND in English.
In future.
If you back your Paypal account with a credit card, you can pay the seller promptly and pay off the card at your leisure. In addition, if the transaction goes badly, the cc has a chargeback service to supplement PP's Buyer Protection service.