Block outgoing spam mails via body or other features

[teknet]

Hello;

An account at our host sends spam permanently. There is a block system via time like a user can send 100 mail in an hour. So this spam spents sending rights in a hour and the real users cannot send because of the block system.

How can i block this outgoing spam mails?

 

[Infopro]

Kill the account. Why would you want to try and work with a spam account instead of stopping it all together?