Hello Chapel-of-apple,
Thanks for the question. I understand you are having issues with the payment information on your account. In my experience, this usually occurs due to the following:
If your account information does not match your credit card, you may get a message stating "The credit card was declined."
To expand on the above, your billing name or address may not match the address listed on your credit card statement. Any discrepancy in punctuation, abbreviation, or capitalization can cause errors, which might prevent you from purchasing from the iTunes Store. If you moved, or if your zip code changed recently, ask your credit card company to make sure their records are up to date and match exactly what you are entering as your billing information.
For more information, see the following helpful resources:
iTunes Store: How iTunes Store purchases are billed
http://support.apple.com/kb/HT5582
iTunes Store: Changing account information
http://support.apple.com/kb/HT1918
iTunes Store: My credit card's security code or zip code does not match my bank's records
http://support.apple.com/kb/TS1646
Thanks,
Matt M.