Hey there,
The only way a buyer could have received an old email address is if you attached it to your eBay listing. This commonly happens when people forget to also update their templates after changing their email address on eBay because it doesn’t automatically change.
If you still have access to this email and you buyer has already paid then you can add and confirm it again on your PayPal account. If you don’t have this email address, advise the buyer to cancel the payment and pay you through the ‘Send Money’ tab to your correct address.
For future listings make sure the email address is correct in the section titled Decide How You'd Like to be Paid.
