The same thing happened to me when I tried to use with an order online. I did the online chat and the rep said it was meant only for people who have ordered just ONE thing during the year, and my record shows several (yes!) purchases.
I said, there is no such message on the card. After a long pause (I suppose he was talking to a supervisor), he came back and said they were sorry BUT I was to get a $10 credit on my account.
I have yet to attempt using it, but I think it's pretty bad on QVC's part. They should have made the requirements clear.