Sir,
1. A wait listed ticket (WL) IF GETS CONFIRMED (right after the chart is prepared):-
(i) Needs to be availed by the concerned passenger, however,
(ii a) if the passenger prefers not to...
more... avail the journey, of such confirmed ticket, or (ii b) fails to board on the train for any reason then he/she can either file a TDR (if the e-ticket is purchased online) by himself or through the agent from where he has purchased the ticket from, stating the reason of his inability to avail the service, thereafter, upon verification a portion of the amount may be refunded to the account from there money for purchasing said ticket has been debited.
2. A wait listed ticket (WL) IF NOT GETS CONFIRMED (right after the chart is prepared):-
You don't need to worry or to take any action....
i. the amount of the un-confirmed (WL) e-ticket/s will automatically be refunded to the debit account from where the e-ticket was purchased by the railways but railways is not responsible for any other service related charges levied.