Hi rituparno.
Sounds to me your ringnecks are not at all tame and could possibly be wild caught if not aviary bred birds.
If that is the case, you are going to have a long road ahead in quietening them down.
You need to take things very slow and do not rush them. Gaining their trust is going to be the first thing to try.
There are heaps of threads and posts on the forum on other members who have successfully quietened an aviary ringneck to the point where the bird will step up, take food from hand etc., just do a search in the search bar at the top.

Depending on the bird, you may never really have a cuddly irn that you can pet like a handraised one would be.