Order not confirmed

On the 12 August 2023 I made an order on an online shopping store called Bigdeal this order had 5 items and only 4 items were confirmed, the one of the huge amount was not confirmed it was the hairdryer costing R2534+ and it automatically got deleted from the cart folder on their system. I have been trying to explain to them attaching proof of payment and items that was confirmed asking them to calculate on their side if the amount of the items that were confirmed do complete the total amount on the proof of payment but they don't help me infect they are refusing to help me or letting me buy other items for the same amount. Please help me Hellopeter I need my money back please