Settings - E-Mail

When I deactivate "sending messages" under "messages" and click on "save", I get a confirmation. However getting messages from my group continues. I log in and look under settings, but "sending messages" is not deactivated any more.

Additionally under "E-Mail-Digests" I cannot choose "send no digest".

I don't want any emails from my group "support assist" any more. How can I succeed in stopping it?