Online order but no stock

On Tuesday 06/02/2018, I ordered and paid for 2 x 5000l ECO water tanks on the online website. Vredenburg Trade depot showed it had 10 in stock, and Paarl trade depot showed 6 in stock. I placed the order with Vredenburg, and the payment and confirmation went through quickly and smoothly. Order was being processed, with a delivery date of today, Thursday 08/02/2018. I phoned Vredenburg around 11 to find out what the status of the delivery was, only to be told they had no record of the order. They then contacted Paarl, only to find out the order was mixed between the two locations. Neither of the locations actually has stock, and so the order will now need to be transferred back to Vredenburg, and only then can a buyer place the order. This means a waiting time of 6-8 weeks on a product that was supposedly in stock. How is this possible? I need answers please.