Domain has exceeded the max email per hour

So i have an issue and it is driving me crazy at the moment , and my coffee just spilled on my laptop .errhhhhh!!!

Ok so I have a VPS server , Cpanel installed , and i have just one client.

every now and then users can not send emails because they get a bounce back. I check the "track delivery" of cpanel and it says my domain has exceeded the maximum emails per hour. AND multiple emails being sent from - Removed -. I dont know this address and that isnt even my domain name.

Please how can i resolve this . I have tried all through the night and i cant seem to figure out a way.

Thanks Guys

 

Ok, i have just configured all the recommendation on the document you sent, i will now observe and report back to see if this resolves the issue. Thanks for your help.

 

I think i replied too soon, unfortunately the problem still persist, i just found out that - Removed - is still sending emails from my account. Is there a way to tell where its sending from ? or is there a way to block that email address completely from sending emails with my server and making my max email per hour exceed?

 

Please have a look at the screen shot . I had to blank out my domain for security reasons.

 

Hello guy, please can someone help. These spammers are making my life miserable. Please

 

I have done all of the above and this guy keeps spamming me. I checked the ip address in that section you asked me to check and blocked the ip through the "ip blocker" yesterday. But today they are using a different IP Address. Is there no sort of way to protect my self against the spammers? there must surely be way or am i fried?