False advertising at Totalsports

On Saturday I went to the shop in Westgate Mall in Mitchells Plain. There was a red sign with 50% off selected men's and women's items.. The adidas garment I took from the rail was R599 - which means that I would pay R299,50. At the till the cashier rang up the item and said that I owe him R394,98. I was confused and said that's not 50% off. I even went back to the sign showing him what the advertised. He than told me and my friend that it is up to 50% off. We disputed it and showed him that on the sign it did not indicated up to 50% off but simply said 50% off. I asked to speak to the manager and was told that the manager was not available. I said that it is false advertising and I would have to take this too social media to inform customers about this. The cashier response was that we can go ahead and do it. I feel that companies should no get away with this as this is misleading customers.