_Can_ whine to the FEC, _can't_ find a vendor that knows how to configure DNS records for sending email.
The problem is that campaigns use absolutely relentless email barrages, often with alarming or upsetting subject lines.
Then their own supporters get fed up and mark them as spam, and you get into the situation you're in now.
I receive 2-3 campaign SMS messages a day, and they all go straight to spam because they trigger Google Fi's automatic filters.