Goods ordered and paid for cancelled by Takealot

Yesterday I noticed that Takealot was selling a 10 Kg bucket of Zodiac Pool Chlorine R 1 and that it was marked at 99% off. This then meant that it was R10 per bucket. I placed an order for 1500 units and bought an airbrush as well. I used one of the Takealot payment platforms ( PayFast) to complete my purchase and make payment for my order. I later received an email from Takealot indicating that I had not made payment and therefore they where cancelling m order. I initially was going to settle for it but after careful consideration realised that these people are taking me for a fool. I saw a product that was being advertised and placed an order for it. I made payment for the goods ordered. They realised their mistake and was looking for a loophole to get out of our agreement by making it seem that i am the fool. Their policy is that I have 48 hours to pay for goods ordered ( paid immediately) they cancelled my order and yet they are in possession of my cash.