I don't think I've got you wrong in you trying to help. I suggested to the others to email support as per your email. Just that I could see a flaw in the process, with mixed messages being given by your system. It's a shame, because the likelyhood of someone accidentally marking an email from you as spam, increases with time, and so the chaces of affecting loyal customers increases.
Maybe a message on the subscription screen stating:
If you have previously subscribed and received emails, but no longer receive email, please email (whatever cakewalk email is appropriate) or click this (whatever you want us to click)
Thanks for sorting me (I hope, I won't know if you have until I get the next email)