UPDATE 2018-03-11: After too much time and effort, I found a crack in the Support stonewall and submitted Ticket #180311-000394 referring to this post.

When I wanted to change payment for the ESO Plus subscription from a bank account to a credit card which I've used before, the ZOS instructions were to first cancel the subscription, then restore it with the new payment information. So I cancelled the subscription. Then I waited more than 24 hours before attempting to restore it.

The billing address which was (and still is) displayed initially by ZOS has an outdated format for the credit card, i.e., the format has since been changed. So I changed it to the correct format with the same (correct) data. However, when I proceed to input the credit card data and finalize the transaction, ZOS insists that "There was a billing address error ....". On the face of it, the software expects me to enter some other data or to use some other format, although the ZOS website commercial transaction software does not disclose exactly why it considers the billing address as a "problem".

As noted above, the billing address which is always displayed initially (after I abandon one attempt and return subsequently to try again) has an incorrect format. The ZOS system does not enable a customer to change a billing address independently from placing an order. That is a serious oversight in the design of the accounting interface. It is not retaining the corrected address format, probably because it encounters a "billing address error" -- which it will also report if I do not change the incorrect format.

Suffice it to say that only ZOS has a problem billing for the ESO Plus subscription. No other firm has any problem charging that account when I tender it as the method of payment for whatever I've bought. So I doubt that there is a problem with the creditor's system. There is no evident reason for there to be a problem, unless, of course, the accounting and/or website software that ZOS uses is sub-par, or the ZOS business records database is corrupt -- whatever.

After three or four attempts, the system refers me to Customer Support and displays a hyperlink to the contact page. However, I cannot log-in there to leave a message about it (see also my other report of that problem in this section).

So now you know. I have already done everthing that I should be expected to do. Now, what is ZOS going to do?

NOTE: I have re-written parts of the original post to more clearly and accurately report what happens when I attempt to restore the ESO Plus subscription.