Very very dissappointed customer

i bought a door online on the 28th Nov 2019 from Builders Warehouse for delivery and chose Zambezi store as it is nearest to me, made the payment the door was in stock, paid for Delivery and was given delivery date 21 Dec 2019. On the same day at 1:17, I get a call from Builders warehouse Gezina ,the lady tells me that they are reconstructing/upgrading their store and all their stock has been moved to other stores, she then asked me what must now happen? I said to her I don't know, you must advice me because your online store did not say anything about stock not being available, I said to her why not move my order to the nearest store with the door? She then said okay. We ended the conversation. I was immediately worried by that because now it seems like this online stock is not even monitored. I kept on checking my order on my online profile and then i noticed that the order has been moved from Gezina branch to Zambezi branch but the delivery date is now the 30th Nov and we are now in Dec. I then sent an email to *** on the 13 Dec ,asking what is the status because now i see the delivery date is incorrect , no response. Today i called their contact center on ***, the lady i 1st spoke was not convincing that my problem is not a problem her response was very worrisome, she then transferred me to the store which is Zambezi and I spoke to Salome who gave me the shocking news when i asked about the status of the delivery. Her response was that "the door is not in stock, they are waiting for it to be delivered to them", I was shocked, I then asked her why did you not call me to tell me that , no answer. Why did the online store allow me to make payment and buy the door that is not in stock ,no answer. So what must I do now? Salome said let me call you back in 10min. I told her no, i need a refund now because they wasted my time I could have gone and bought the door where it is available, and she said let me cancel the order and I will call you back. That was 20min ago and Im still waiting. I have ordered stock twice on line from Makro Silverlakes and everything has always been on time and as displayed. Communication by sms and email as promised was done. i need my refund today so that I