Questions

In your cPanel you have Global Email Filters = applied to all mail addresses in your domain and local Email Filters = applied to a specific mail address.

go to: cPanel > Email
click Create a New Filter
select Rules, for example: Subject - Contains - "I have hacked your account"
then choose Action, for example: Discard Message
finally, click Create

if you have problems setting Filters let us know and we will do it for you.