[Resolved]  Swiggy — Grocery order not delivered but amount charged

I placed a grocery order on Swiggy-
Order#[protected]
Order Date: 13th Dec, 2020

I never got the delivery. And they cancelled the order saying that they tried to reach me over phone and I was unreachable.
I questioned why couldn't the delivery person just ring the bell or knock at the door. We have order 100s of times in the last few months. Even yesterday there were a few orders delivered from various places (Amazon, Medplus, BigBasket etc.) and every time the delivery person just comes and knocks on the door or rings the bell (even if rarely I am unreachable by phone).
This is the basic delivery etiquette and business practice.
But Swiggy representatives didn't listen to reason at all. They just said they tried to reach me over phone. There can be many reasons of not picking the call. My phone wasn't responding at that time and/or I could be in another call. They didn't accept the mistake of their delivery executive for not knocking the door or not even trying to ring the bell.
I requested they redeliver the same order. They refused that saying they had cancelled the order. They even refused to refund the amount stating it's a non-refundable order.
Even trying to escalate the issue to the supervisor, and my experience conversing with him was equally disappointing. He didn't accept the fault either and just tried to put the blame on me.
Now delivery services have been there for 100s of years, it's a basic practice for the delivery person to ring the bell or knock at the door. This Swiggy's delivery person didn't even attempt to do any such thing but went away with my order.
I lost the amount paid, as well as so much time interacting with them, not to mention my peace of mind.
Kindly refund the amount in full, or deliver my order immediately.