Can no longer receive email from a particular address

I subscribe to an email newsletter and have for years.  Recently the administrator told me that all his emails are being blocked by Cox and he could only communicate this information by sending it from another address.  I am very frustrated trying to find a place to email this problem to as Cox apparently does not want to hear from their customers by email for some reason

Is there an email address for residential email customer support where I could send them this concern and give them the email address that they are blocking so they can unblock it?

thanks for any help,

           mimbler