Wave cable uses a company called Synacor to provide their e-mail. Synacor is allowing spammers to use their servers.
We have had this problem ourselves in the past with hacked accounts being used to spam. We have solved it by installing fail2ban to limit brute force password attacks and postfwd to force a password change if/when a clients account is abused. It detects abuse by looking for a customer coming from IP’s in three or more countries in 24 hours. This pattern only happens with botnets which spammers are using to send their spam.
If anyone knows how to contact their network or mail administrator I’d be glad to point them at these resources.
When spammers use unclean e-mail lists that contain addresses that don’t exist on our server, it triggers a program called fail2ban to ban them after several unsuccessful attempts because it thinks someone is probing for user addresses to spam.
I have unbanned their servers twice but as long as they continue to allow their resources to be used for spamming, mail delivery from wavecable.com is going to be problematic.
If you are a customer of wavecable, it may help to complain to them that your e-mail is not being delivered because of other customers on synacor.com’s servers abuse them.