I continue to have this issue. Although I can't say it's all. "maine.rr.com" and "roadrunner.com". I discovered it when I myself didn't get a campaign email. Found I was suspended. Two months in a row. Your customer support cleared that each time. The second time I looked closer at my bounce list and 27 suspended. All TW/Spectrum. When I pressed the support agent why this is happening, I was told it was a TW/Spectrum issue. I managed to find some time today to do some research and found this thread.
If your contacts are constantly bouncing back as suspended, something to have them try is adding your email address to a whitelist. Your contact can tell a security program that content from Constant Contact is okay to view by putting Constant Contact's domains or IP addresses on a whitelist, which is an industry term for a "safe" list. This should help resolve the issue with certain domains not receiving your emails due to bouncing as well.
This just happened to me too. I believe it's because Time Warner is now Spectrum and they eliminated all of their RR email accounts. Customers had to change their emails to spectrum.net accounts.
I apologize this is happening with your contacts as well! Because this is happening with contacts that have the same domain, I would suggest having Constant Contact whitelisted in their security settings. If these contacts continue to bounce after whitelisting, feel free to also reach out to our Deliverability Specialists. These support agents can help look further into these contacts or any other contacts that may bounce in your account.