SRS Travels — Delay in 4 hours even not traffic bcoz of parcel service

We travelled 6 members from bangalore to kumbakonam on 19th august 2016 it suppose to reach 5:30 am at kumbakonam but it reached on 9:35 am. Bcoz it stopped for parcel in hosur, trichy, tanjavore.
Also we booked return ticket on 20-aug 2016. Due to this delay we have cancelled the ticet and booked in green line travels.
We requested not to do cancellation charge. But in customer care they said we don't have option. If its delay we are not responsible. If its due to traffic its ok.
But you already know number of parcel you should take. Bcoz of your mistake we have loss 50% of amount by cancellation
Pnr number[protected]Banglore to kumbakonam)
Pnr number[protected]Kumbakonam to bangalore) cancelled