If your customers have an existing Pay Pal account then they have to login to it to make the payment. If they cannot remember the email address they used and the password they assigned to their Pay Pal account then they cannot login and cannot complete the payment.

If people bought off a website a couple of years ago then it's likely that Pay Pal pushed them to quickly create a Pay Pal account by making it difficult for them to see how they could pay without creating an account.

These people then promptly forgot that they had created a Pay Pal account - but unfortunately Pay Pal doesn't forget.

Vger