Editing Credit Card doesn't save CCV number - ACcount Settings

Editing Credit Card (in my Account Settings) doesn't save CCV number - I've been unable to get to the bottom of why Amazon has been unable, since Oct. 1, to charge my credit card for my SmugVault service. Everything is correct with Amazon as far as my card number, address, etc. etc. And my bank has even verified that they've approved the payment. But Amazon can't get my card to work for this tiny SmugVault charge! In re-entering all my card info here on SmugMug (Account Settings), since I had recently gotten a new card, I see that no matter what I do, the CCV number (3 -digit code on back of my card) does not save. In other words, I save the changes, & if I refresh or go out of settings & come back in, all the info about my card is there except for the CCV number. It's as if I never entered it. I'm wondering if this has anything to do with the problem-- I'm just following every possible glitch. It's ridiculous how much time I've spent trying to figure out why a $4 charge simply will not process!!