The way i deal with xcessive phone callers is to
1. Use voice mail. Get people in the habit of being called right back if I am available.
2. Encourage email use for non urgent matters.
This really depends. If you have responsibility for a production system that is supposed to be running 24/7, of course Ops will and should call you if there's a problem.
But if you have no such responsibility, you can route to voice mail.
3. Get rid of the thing.
Mine has an "Off" switch...and I've never activated any forwarding or voicemail.