MR Delivery refusing to give me a refund

I tried to place an order on the MrD app and when I tried to process my order for payment there was a pop up error and the payment could not go though, I tried the exercise twice and I got the same error. I later found out one order was delivered. I called the hotline and I was told that because the order was accepted I could not be refunded. I requested to talk to the so called supervisor and she informed that it was my responsibility as a customer to call the line and confirm if my order went through. Now heres my problem, when the app gave me error messages twice when the order was placed, there was no communication from the app that I need to call and confirm if my order went through. I indicated that the food has not been touched they can come collect since they are enfersing that I excepted the order. An order that did not indicate the order was accepted or the food its on it's way. To add on to the insult the so called supervisor hang up the phone on me, the customer that is being inconvenienced with charges due to the error of the app.