It sounds like they're trying to protect you...well, from you!
It looks like a safety measure put in place from brute force attacks to try and gain serious access to your account. That's why they want back up documentation to make absolutely sure it's you, and not a scammer out to buy stuff through Paypal with your account, using a (possibly stolen) credit card.
I doubt calling Paypal will help at this point. All they're going to tell you is you can't verify anything over the phone, they need the physical documentation, or another credit card.
If you try another card, make absolutely sure you type in the information EXACTLY as it appears on the card. If your middle initial is on there, put it in the box. Double check all your numbers, especially your 3 digit code on the back. (believe me, I've been guilty of skipping cc numbers!) Your name MUST match the one that's on the account, so you can't use someone else's card to do this.
Good luck!