They can measure the location of the break to centimeters by timing how long a light pulse takes to reflect back to the emitter. It is called time-domain reflectometry.

Ok, then was it used? And if not, why not?

It was almost certainly used.

What was the response?

Why are you assuming that would be released publicly? The person you are discussing this with is simply informing you of the existence and availability of the technology you're asking about.

They now the distance to the break from one end. They then use that with a map of the cable to determine the lat and long of the break and send a ship to fix it.

So, no navy involved? With such a system I would expect them to catch the perpetrator red-handed and raid their ship, etc.

This process assumes the damage is accidental and doesn't involve the military. If Russia keeps cutting optic cables that could change. I can envision military ships getting real-time notification of fiber cuts and the current location of all foreign ships.