Temporarily blacklisted IP Address

My Ntlworld email stopped arriving. At the same time my wife's email stopped. Both said that the passwords were invalid.  We changed our passwords - my wife had to move to a VMo2 ID. We generated APP passwords and put them in - no change.

I rang help desk in India - they said that the problem is that they do not support NTLWORLD addresses any more. I said that was amazing and asked for it to be escalated. The assistant arranged for me to to be called by his supervisor the following day (Sunday) at 9 to 9:30.

Then I noticed on my Macbook i had a different message - Temporary blacklisted IP Address. I checked on this forum and found that I could access my mail by using my iPhone as a hotspot and it worked. I could also access the email via the browser.

No supervisor rang between 9 and 9:30, so I rang at 10, to find it hasn't been escalated. I was asked to clear browser cache/ reboot the router etc. etc. I then asked to be escalated to their supervisor, who again said they could not help as support has been dropped for NTLWORLD Addresses. He said they had been told that the domain had been turned off and this means that no emails will get through any more.

I filled in a security report and forwarded it to the VM security team. I want to know what the "suspicious activity" was and asked that they lift the blacklist. This is the third time this has happened admittedly the last time was two years ago, when my solicitor sent me a message that was encrypted internally.