Makro - online order deliveries

I am a regular user of Makro online. The inconsistency with deliveries is just ridiculous. Sometimes it arrives the day after the order is placed (then I am overstocked and dont have space to store the items) other times it take 4 or 5 days. It is impossible for me to run a business when there is no guarantee of a delivery date. I run a tuckshop, so this is is not working for me, as I either have way too much stock if they deliver withing 2 days or run out of stock when they don't deliver timeously. I am currently out of stock of almost all my snacks, which is most embarrassing for me. I received an SMS yesterday to tell me I would receive my delivery today, however when I called the store for the 4th time(Woodmead) my order has not even been collected by the courier!!! If Makro want to retain customers, I suggest that they get the online system streamlined. If you are too busy, then employ more people to cope with the load, not tell the customer that you are too busy, so it will take longer to deliver than it usually does. Very disappointed customer!!!!