Cylinder leakage problem

You don't need to pay anything for checking and fixing it

Yup, you don't have to pay. It's part of their job.

First did you register a complaint? If not do so. After the service engineer checks, max he recommends is regulator change and try to sell suraksha pipe. 

Did you swap the cylinder today with a new one and facing this leakage?

If yes, then, the most likely issue is with the rubber ring inside the nozzle of the cylinder. Either it is damaged or not present.

You can take out the ring from the old cylinder (with a screw driver) n put it in the new cylinder.

We had this situation once few years back. The delivery guy came and changed it within a second using a key (instead of a screwdriver).

Check YouTube videos for this.

Black colour Waisher change usually fixed the problem.

Complain to agency they will send the person who will change Waisher and if problem not fixed they will change the cylinder.

I had faced this problem a couple of time. First call 1906, register your complaint and they will send representative at the earliest . Most of the time delivery boy will come but if he's not available someone else will come.

Have never paid them, they never asked.