So they ignored 90% of the content of my message but ultimately said exactly what I expected regarding the solution about emailing SE a picture of your credit card:

Dear Customer,

Regarding your request for account support. Please find your answer below.

Unfortunately that service is not available at this time. Suggestions from our customers are always valued. While we cannot guarantee implementation we will surely pass this on to the developers.

...
The rest was a copy paste auto reply of what we already know (with continued blame pushing on my bank lol). And the suggestion that I should effectively give up on my extra retainers, and continue to pay more than the standard for subscription fees using game time cards until this magical paypal solution becomes a thing.