Dyson Misled Me on V15 Discount Then Ignored My Urgent Cancellation Request

I wanted to purchase the Dyson V15 cordless vacuum cleaner using the discount campaign for customers who already own a Dyson device. First, the lady who contacted me over the phone informed me that the highest model available in their stock was the Dyson V15 Detect Absolute. I confirmed that if this was the only model in stock, I would proceed with the discount campaign accordingly. What happened next was a complete disaster: The lady on the phone misled me. When I checked the Dyson website, I found out that they actually had the V15 Submarine model in stock. I placed my order on Friday and immediately requested to be contacted and have the order canceled. No one got back to me on Friday, and the order was shipped! Today is Monday, and despite specifically asking to be contacted on my personal phone because I was planning a surprise for my wife, they called my spouse’s phone instead! I reached out via WhatsApp, only to discover that my case was closed without even speaking to me, with the response that "a new discount cannot be applied"! I opened another request, yet no one contacted me by the end of business hours today (Monday). I have never encountered a customer service team that takes days to respond to urgent requests. My expectation was clear: the lady who misled me should apologize, acknowledge the mistake, and offer a solution—which would be to sell me the V15 Submarine model (since it is in stock) and apply the discount I am entitled to! Now, I am left wondering—will they even respond by Tuesday?! This has been an absolutely terrible customer service experience!