FALSE ADVERTISING!!!!

I went to Earthchild Maponya Mall today to collect the items i bought online. As i entered the store i was greeted by this beautiful Green dress which to my luck was on SALE. The sale price tag indicated that the dress is now R240. A perfect price for me as i was buying it for my niece as a gift. When i got to the till to my suprise the cashier then said the dress is R270. I then quickly referred her to the price tag. She then said the price on the price tag was a mistake, according to the price on the till the dress is R270. Upon realising that i was not gonna be allowed to pay the price as per price tag, I then paid the R270 as stated. I could clearly see that the store is not willing to accept that this was actually false advertising on their part and that as a consumer my rights are that i need to pay the price as stated on the Tag. However, what is really fustrating to me is that the Manager was just next to her all along. She came and said to the Cashier, whispering, there is nothing i can do!!!...Later after i took a picture of the price tag in front of them, she came back again to find out if i had paid for the dress. All this is happening between herself and the cashier as they are whispering to each other without noticing that i can actually hear them. She didnt even ackowledge my presence or try to resolve the issue at hand. She said to the cashier, i was going to override the amount . The Cashier then said, NO she has paid already. To me, this was just a sign enough to say as a customer i am not valued. Both the Cashier and the Manager were quick to dismiss me. I am totally not happy with this as i paid R30 more for the dress and if i probably did not have the R270 i was gonna lose the dress just like that! Since nobody seemed to care. The customer service i received at this store today is a definate ZERO!!!!