email that says my credit card on file has issues

I wouldn't click on a link in an email. Too much phishing looking very like an email from Apple. Check directly with this method:

This document explains how to 'Change, add, [review,] or remove Apple ID payment methods' on an Apple mobile device, a Mac, or a PC; click here --> https://support.apple.com/HT201266

Issues will have red lettering.

FYI:

Identifying legitimate emails from the iTunes Store - http://support.apple.com/HT201679 - lacking in specifics, the next link is better:

Recognize and avoid phishing messages, phony support calls, and other scams - https://support.apple.com/HT204759

Still, the safest method is just to use contact methods on Apple's web site rather than hoping you aren't up against some expert scam.