If someone is controlling your mac laptop/desktop you need to disable screen sharing, it is an easy fix:
Here is what you have to do:
Logon as an admin.
  1- Go to "system preferences", go to "sharing", The options you wish to   uncheck are as follows: 
  Remote Management 
  Remote Login 
Screen   Sharing 


2- Enable your Firewall: 
Go to "system Preferences", go to "Security", Click "Start" to enable firewall.

3- Click "Advanced" Click on "Block all incoming connections" or enable "stealth mode", and "auto allow signed software to receive connections"

(*) You may need to unlock these items click on the "padlock icon" in the lower left corner and enter the admin name and password.
Wessam