You may not get this to work.
Postfix is a programme that listens for incoming messages and delivers them to recipients, usually a spool file locally, it doesn't collect mail.
Postfix will allow local clients to send mail outwards via it's smtp server, which adds some extra complexity if they can send via pop.net4india.com directly.
To collect the mail from a remote server you need a POP client programme, eg "fetchmail
" to collect and store locally,
& to read the incoming messages, you need at minimum a POP server for clients to talk to, eg ipop3
, which runs from xinetd.