I don't believe I created a new account. I went to the first part a couple of weeks back on the apple ID support and changed from msn to comcast. But then went to the change information link, and it defaults back to the original credit card number and so I've tried to update that information (same account, just a reissued card with a new number), but it keeps sending me back an error message, won't allow me to amend with the new card, and won't allow me to make any transactions (which makes sense). So right now I'm not allowed to make iTunes purchases and I can't add in a family plan on iCloud. Very frustrating.
I used the link above you sent me, but still it reverts back to the old credit card # and sends error messages when I try to fix.