Q: why is it asking me for my credit card info?

I was at home when I saw the new update for Snapchat. I went to the app store to upload my Snapchat and it said it needed my credit card info. I was confused because I already had my info in there for so long. so I press continue and I put it all in all over again, and it said it was declined. I thought I had no money in my card anymore but I do. I don't understand what's happening.

HELP ME!!!

-Ruby ❤️os