The WORST online order experience EVER!

I bought a microwave online on Sunday, 25 February 2024 and I have not received it yet. I called them on Friday, 1 March only to realise that they were not aware of the order at all! I was promised that I would receive it yesterday (Monday, 4 March). I STILL HAVE NOT. Sent an email to the store and they gave me a sob story of how they have no stock and are still to get some. I don't understand why they sell stuff they don't have on hand.