Ordered was canceled and I was imposed 100% cancellation fees

I had ordered a pressure cooker (3L) from Swiggy Instamart, order ID [protected], registered mobile number [protected]. I cancelled this order because I had mistakenly ordered the 3L size instead of the 5L size I wanted. At the time of cancellation, I was told by a Swiggy executive over phone that my money would be refunded. This was also confirmed in writing in the chat support, where it was stated that the refund would be processed. However, Swiggy has now informed me that a 100% cancellation fee is being imposed on me. As a result, I have neither received the pressure cooker nor received my money back. I request Swiggy Instamart to honour the refund assurance given to me by their executive and in chat, and to refund my full payment for this order without deducting any cancellation fee. I want my refund