Swiggy instamart - Product not delivered and being charged

I ordered few items on **th Oct'** amongst which D'lecta Grated Italian Hard Cheese was not delivered by the vendor. The vendor contacted me and said the item is not available he can provide me the replacement. I denied for the replacement and asked him to refund, to which he agreed. But neither the item was delivered nor the refund provided. He charged me for the item in the bill. I raised this with swiggy instamart support team via mail. They reverted with the response stating they an't provide me refund or replacement because they can't validate my claim. I have shared my call recording with them still they continued with their response of not refunding.