Cancelled items in an order

Such inconvinience and disappointed in online purchases. This is the 3rd time this is happening. After placing online order a day or hours later receive sms that some of my items are cancelled. Last 2 times some details said item is no longer available, which doesn't make sence why did it show in stock while in cart. Now this time I don't know the reason but 2 items cancelled ( 1 on promotion and I wanted it soo bad another is my kids snacks) I thought I saved shopping time to do other shopping that require me physically in shop now I must still look for these cancelled items. It's disappointing. Makro online orders are then not reliable. Because why cancel certain items in a confirmed and paid order.now I must worry if my money will be refunded, some of us have busy days at work and home it's really disappointing, now I must keep track of items cance9and not think delivery didn't do the right thing.