Apply Limitation with SMTP

Hello Community, I am using Carbonio 25.3.1.

Recently one of my users’ computer got infected with malware and sent about 5 million emails. Which put my server/IP/DNS in jeopardy.

In Zimbra there was an option using which I could restrict users from using POP/SMTP. To do email communication, they must use webmail. I cannot find such option in Carbonio.

Also is there any option I can limit SMTP usage, like one user cannot send more than X number of mails per hour or something like that?