Automated email with Paypal?

Ok so! I'm currently running a Pay what you want sale on some games I made. It is set up to use a Paypal donation system, when the buyer clicks Return to Merchant (the site tells buyers to do this) it downloads the game in a zip file.

However sometimes people don't click it or if there's heavy bandwidth it takes a while and some people think it isn't working - in these situations they manually email me and request their download link.

It works fine for me since I'm almost always in touch with email. However! I'm off on holiday in a few weeks. So I'm faced with either stopping the sale or coming up with some way to automatically email people the link to the game.

Ideally I'd rather not like to leave my iMac on during this time. So what options do I have? Is there such a function buried in Paypal to automatically email people after donating/buying a product?

Any help would be so massively appreciated!