https://comcast.e-redemption.com/
After you fill in the information take a screenshots of the page and save them to your computer.
If you get a confirmation page take screenshots of it.
If there are any problems later you will have something to present to Comcast.
FWIW, here is the fine print on the redemption page
Coupon good for a credit toward your Comcast cable bill for On Demand programming. Not available in all areas. Restrictions apply. Offer limited to residential cable customers with Digital Starter or above and accounts in good standing. Please allow up to 60 days for the credit to appear on your account. Limit one coupon per household. Coupon is nontransferable. May not be combined with other offers. Not valid for special events or adult programming. Comcast employees and immediate family members not eligible. © 2012 Comcast. All rights reserved.
edit to add: don't throw away the coupon. File it in a safe place. Don't forget where you put it. Once again it could come in handy if you need it. It also might be a good idea to write down the name of the PPV you ordered and the date.
Comcast employees must be authorized to post in the forum. Employees posting here have their names in red and are designated as employees. Names not in red are customers.
