Swiggy — rs. 500 cancellation fee for cancelling within 3 min

Address:

Old Madras Road, Virgo Nagar PO, 560049

I made an order for rs. 995 using the swiggy app. Within 3 min, i realised that i made a duplicate order so i submitted a cancellation request, i was charged rs 500 as cancellation fee. I was informed the rs.500 was charged because the restaurant already started preparing the food. So, i requested customer service to restore the order because rs 500 was too steep. I'll instead eat the biriyanis, they said they can't do that either.in a matter of 5 min, i lost rs. 500. 50% of the bill. Is this justified. If returned the food that came home then i'd feel nobody in bangalore would order biriyani so rs. 500 is a little justified. But, this kind of ruthless business model is unacceptable. They are market leaders and find it totally their rule.
This is plain 'daylight robbery'. They charged for me for no service. I wonder how far they went in making a biriyani in 3 min that rs 500 as cancellation can be justified. Ruthless and savage business policy.