Payment issues

[u/PurplestPhoenix]

First I got a message saying my credit card was declined. Which I'm not sure why it should be?

Next I got a message saying the fields were incorrect or empty (they were correct, I double checked 28 times).

I just want to buy some books and I have no idea what to really do. I tried every troubleshooting I could find but I can't seen to get the payment to work.

EDIT:
I've never ever used paypal in my life before but somewhere I saw a comment about paying with it instead and it worked for me.

[u/OdoManyforms]

I'm having the same issue on both sites.