For weeks I've been getting 10-20 delivery failure notices a day. Somebody has chosen one of my domain names to sell Viagra. I immediately checked to make sure I had my SPF records in place, and they were there not - so I added them. Doesn't seem to have slowed anything down, though.
It sucks because at this point, since my addresses have "sent" so many, I'm receiving one spam email every 45 seconds, 24/7.
Is there any other option I may have?