I got that, too. The coupon says to mail it in with your bill payment. I have a recurring payment set up where they automatically deduct the money from my bank account so I don't send in a payment. Do you know how I would use this? If I call CS, will they put a credit on my account for the amount?
I send my payment via my bank's BillPay system, So I am in the same boat. A few years ago, when I got a similar coupon, I called TWC and asked them what to do. They said to order the movie, and then fill out & send in the coupon. With the account # on the coupon, they will be able to credit your account. I'd keep a copy of the coupon, just to be safe.