Selling out of stock items

This company sent through a quotation on the 20th of February 2023 that is valid for 7 days. As I wanted to pay the invoice on 21 Feb 2023 something told me just to check if its actually still available it was not (this is after sending 3 emails and till now still no response ) , i phoned the company and they gave me Nelson’s contact number, I contacted him and he said he will look into it and give me a call back. Jabulani then contacted my partner saying there is one in stock and he will open it up on the online shop as well as add the cover as this was not in the shop. Really they did open it up to say there is one in stock and i could even add the bag! As I made payment and received my confirmation email literally not even 5 minutes after all that they phone to say it is out of stock. Now my question is why go through all that trouble to open it up to get payment when you are fully aware you have no stock to sell?! I mean really?? It is horrible service and good luck to anyone wanting to buy from them.