The service is called DigitalRepoMan and it will automatically shut down access to a digital product after a refund is
issued by you. 

What is great about this service is that it limits usage of a digital product based on a computer's unique "MAC Address".

In other words, it is not IP based which can easily be hacked by anyone with a brain.

In easy to understand terms, if someone requests a refund, the digital
product is no longer accessable,its just as if it was returned
to the store!

I highly recommend taking a look for yourself at it and take the 7 day test drive.

http://jps6108.thesecondtier.com/digitalrepoman