How to disable chron jobs?

Although none of the sites hosted within my WHM account use chron jobs,
I believe that a chron job has been deleting our emails (ie., perhaps
as set by a hacker or another reseller on my same server).

Is there a way I can completely disable the chron function within my
WHM account for all my sites?

In advance, thank you.

 

I use Squirrelmail on my server (-- not elsewhere).

Further, I continually check our settings to assure that we're
not blocking ourselves.

Reason I ask about disabling chron is that I set the chron
several times to activate once a month, just in case we
were hacked. When I check back a day or so later,
other settings have replaced mine. This simply
makes us suspicious of having been hacked.

The shortest correction step to us appears to
be to simply disable the function altogether -
as we do not use it whatsoever.