The Nisene RMA features automated mail processing so that any activity that occurs through this system is logged, and then sent via e-mail. If you never received a confirmation of your RMA, there is a good chance that this automated message was filtered out as spam by your corporation's mail server.
Another possibility, although rarer, is that you entered your e-mail address incorrectly. In this case, there's nothing we can do to deliver your messages; however, in this case you can always call us directly and we can update your account in our system so that not only will all future messages be delivered, but you will be able to log yourself in and see the history of all of your tickets under that (now corrected) e-mail address.