False advertising by cash converters

Hi i pls want to share my concern over this shop particular i bought a smart tv from them and on the slip as well as the price labels the item it says and describes the item as 65 inches , i was moving into a new dwelling and set the smart tv up and the was no problem with the item working but took a measurement of the screen and found that it was under 50 inches . A new tv of the exact make and size is currently selling for R5000 and i paid R5500 for this secondhand item of wich the false advertising said it was 65inches and it is not , at the shop the manager as well as the staff argued that if you look on the back on the serial number it shows its 55inches although if you take a tape measure and measure it ,it comes at 1240mm wich is 48.8 inches. Pls do not support this shop as they advertise false and dont label items correctly.