"An AWS consultant who’d been covering my bills disappeared". I wouldn't be surprised if the payer filed a chargeback and then AWS went nuclear.
"The post-closure period is 90 days—during this time, an account can be reopened and data is retained."
If they don’t “know you” financially you’ll need to jump through compliance questions before your new payment method is accepted. If you don’t verify the email verification mail within the 5 days I imagine you have to jump through more hoops, which this person didn’t do in time.