Makro - says its my fault for not checking the receipt even though the amount paid is what i expected to pay

Saw a Samsung 9kg machine on special for R7499, went to Makro-Silver Lakes - 26 August 2022, to replace my toploader. The staff at Makro tried to convince me to buy a LG. I was specific that i wanted a bigger front loader and the 9kg was the specific machine i wanted. I need to point out that after i had informed at least three of Makro floor staff that I wanted a 9kg that was on special- which they were suprised by as they said they were not aware, including the warranty gentleman, Ms Rooi took the code, asked me to wait for the guarantee paperwork and asked me to follow her to the cashier. I still indicated that the machine was on special across a number of stores including Hirsch's which is close to Makro. I took delivery of the machine and had the machine installed. To my horror, earlier this afternoon when offloading my laundry noted on the flap that the machine i have been using is 7kg. I went to Makro and was informed the Sales Manager Sekgale about my unhappiness with the fact that i was sold a low capacity machine for a price R7 499 which he claims was the same price for a 7kg (it boggles the mind). He politely told me that because i opened and used the machine, there is nothing they can do, insisting that i should have looked at the receipt. She handed the code to the cashier, gave me the 3 Omo auto liquid (2l) which I paid the expected amount R7 499 plus R99 for a wired mouse. I proceeded to collect my "9kg" machine in a box that did not have a clearly marked capacity. Not once did anyone, including the cashier or the warehouse confirm that i was paying and collecting a 7kg machine. Truly disappointed as i have previously bought and collected from Makro without any glitches.