Pick n Pay ASAP costs me money

When I place an order on the ASAP app, Pick n Pay places a reservation on my credit card for the value of my order. Fair enough. But if they are unable to deliver even one item because it's out stock, or if there is a price difference, they charge the new value to my card, but leave the reservation in place. It takes at least a month for that reservation to be released. Result: I am out of pocket for the value of the order for a month or more. This week alone it has happened twice - leaving me with R1600 of MY money that I cannot spend because Pick n Pay is blocking it. Phoned to complain, lots of tut tutting, no action. A week later, still waiting for someone to get back to me. Pick n Pay you need to fix your process, or say goodbye to customers. Checkers and Woolworths have got the process right. What's wrong with you?