Does someone know how long it takes Pay Pal to bounce a payment back to a buyer.

My OH has just sold an item using an old template he had in the system, as we have changed our e-mail address he updated it and double checked he had updated it on the template but when he listed the items the e-mail address defaulted to the old address.  He did not realise this until someone had won and paid and the hour glass came up.

He has sent an e-mail apologising to the customer for the error but we don't know how long it will  take for PP to return the payment or is there anything our customer can do from their end.