Jet Airways — Cancelling flight booking without notice

Hi,
I had a return trip booked by an agent from 9th to 22nd february. Due to certain reasons i couldn't take the flight on 9th and got that ticket cancelled specifically.
The 22nd reservation was still showing with the given PNR.
Even om the night of 21st february I had opened the portal for web check in and it was opening with the same pnr.
When I reached the LKO airport, the jet airways people told me that both the tickets had got cancelled from the system since It was a return trip and I hadn't travelled on 9th. Instead I had booked a ticket for 12th and reached LKO through jet airways only.
Due to this system error I wasn't allowed to board the flight and I had to reach bangalore so I had to forcefully book in Indigo with a fare of Rs. 10000+ and come back because there was no room in Jet airways flights.
I was a lone female travelling and at least I should have been informed through mail or message that ticket has got cancelled. I am attaching both the tickets. PFA.

This kind of inconvenience caused is totally frustrating and heavy on the pocket as well. Revert to me that who will pay back the difference in fare and in future avoid such mishaps.