Faulty online ordering system - major inconvenience to me as a customer

1. Ordered item after confirming availability online 18 June 2023.

2. Confirmation of order email received 18 June 2023.

3. 22 June 2023 - receive WhatsApp message informing me item I ordered is not available, therefore I should choose from 2 other alternative items

Concerns:

1. As a premium brand, Kingsley Heath ordering online system is really bad. Why would your system reflect that a certain size is available, yet that is not the case?

2. 4 days later, the store realises that ordered item isn't available. .... That's really bad customer service

3. Arrogance by store representative who assumed that I'd be interested in 2 other alternative items.... I chose the concerned product mindfully and deliberately....

4. I have been inconvenienced as a customer and have had my expectations raised.... I believed I'd get the item I purchased after receiving confirmation email, & I was looking forward to the item, as this is a need to me at the moment.