Cancelling a order

I order a Philps Air fryer from takealot and like 10 minutes later I wanted them to cancel the order because I changed my mind and wanted to the the more expensive but was told that they can't because the product was already be prepared for shipping.

All it would take is a call to the warehouse to tell them to stop processing the order but unfortunately, I had to get some thick head person who couldn't even try to help all they did was repeat the same set of pretyped messages that they have.