Swiggy — Cancellation fee charged wrongly

I have placed an order in Swiggy in Aminia restaurant. Just in a minute I realised that the quantity confirmed for the order was wrong it was 1 instead of 2. I raised a request for modify/ cancellation. They have deducted the whole amount I paid Rs.141 immediately. I spoke few customer care executives also. They have told that it is the company policy that they will charge full amount as cancellation fee. The invoice shared with me is just Rs. 50.05 plus tax which equals to Rs. 59.05. Whereas they charged me Rs.141 as cancellation fee.