Misleading & Overcharging

This is day 6 and still haven't received my online order from Pick and Pay. First order placed on Thursday, 26 November to the value of R3711.35 for delivery on Saturday, 28 November. On Saturday, they wanted to charge my Discovery card, R4559.00, R847.65 more, how is this possible. My card declined as I only have enough for my order? Why charge me so much more? No communication from Pick and Pay? Again I placed my order for delivery on Tuesday, 1 December. Again they send a order confirmation of R3781.26, once again I received a notification that my transaction is declined, why? Again Pick and Pay want to charge me R783.17 more than my confirmation. I am inconvenienced, charged decline fees and all that Pick and Pay customer service is saying we are looking into it??? Still awaiting response on the huge difference in prices?? I placed my order again for delivery for Thursday, 3 December, the order confirmation again is for R3794.41. I wonder how much more they going to charge me this time and if my order will actually go through this time?? The worst service ever and the only one loosing is me, no urgency or priority for Pick and Pay to resolve my query or getting my order to me!!