Me Delivery is a complete *******

Second time this has happened to me. I use the MrD app and am charged the full amount. I then receive a message that the restaurant has rejected my order. Call center calls me to explains that I have been refunded - however I am really not confident that they will actually refund me - they didn’t the previous occasion this happened. More so they make it my responsibility to pursue the issue with my bank. Why do they deduct funds before placing the order with the restaurant? Don’t use this app - they are a *******.