How to redeem a digital code of a movie without a credit card?

Hello!

I have bought a blu ray movie and it came with a digital code of the movie. I tried to redeem it in the store (it is an apple code), but I get a message that they couldn't "charge" my card for some reason...

Why do they need to charge my card, it's a digital code from a purchased movie.

How can I redeem it without having to enter a credit card, which I really don't want to do.

Thank you.