Mimecast service levels and reliability

[OCP]

Long time Mimecast client but getting fed up with their lack of support.
+ No replies to support emails
+ telephonic support is now an extra bolt-on package
+ twice in the last week has one of their servers been blacklisted causing mail delivery issues.
+ numerous email delays on Mimecast side that we are still waiting a full explanation on.

Anyone else experiencing the same?

 

[Web Telecom Services]

Mimecast IP addresses are blacklisted very often from what we can see on our blocked incoming, we sometimes need to whitelist many of their addresses just so that our clients can get important emails and statements.