Final update as it has been nearly a day now: no response from support. :)

Changing the email address associated with my account to one that hopefully isn't blocked in the future.

Question in case anyone actually sees this: What downsides would there be to whitelisting email addresses associated to active/paying customer accounts? Seems like a no-brainer move to have your customers whitelisted to send you email if support is primarily done through email. I understand blacklisting domains known for abuse/spam but whitelisting individual accounts from that domain that are paying you seems like a good compromise having only put 5 seconds of thought into it.