User has to know which list emails he is not receiving. Then the users can check their subscription status from the URL" http://lists.iitk.ac.in/mailman/listinfo/".
In the above webpage, after going to "Unsubscribe/Edit Options", login with email iD, list password.
Please note this web interface does not use CC email password. You can get the password by checking "Password reminder" section. the password will be emailed to you.
After login, make "Mail delivery" flag as "Enabled" to start receiving list emails.
To enable Digest mode, put "Set Digest Mode" On.
You can also change your list password. Do not use a valuable password while setting/resetting password in list server.