Hi, I'm Pete. Welcome to JustAnswer! I'm reviewing your question now, and will post back with your reply ASAP.
Have you tried restarting the Kindle?
Just checking - did you press and hold the Power button for a full 40 seconds to reset the Kindle?
If that didn't work, check that your payment information is up to date on the Amazon website.
If it still won't work after checking your payment information, let me know the exact error message you are getting...