[deanhills]

It's been installed since this house was made!
But the problem is
The front door was broken by a thief! So I need a security upgrade for all existing doors

No place can be worse than South Africa.  You need a very heavy front door, with a double lock and an iron gate.  Depending on your budget, you'll already be better off if you can install an iron gate with a double lock.  I Googled our area instead of buying one from a shop, as it's important that you get an iron gate that is galvanized so it won't rust and will last for a long time.

In South Africa every one subscribes to an Alarm Response service, but I imagine where you live, it's maybe not available or too expensive.  I'd vote for the iron gate that is hand made by someone who is a specialist on gates, and who is installed by him in such a way that it cannot be removed from the door frame.  Mine was very securely attached.