Refusing to give the discount price

when into store and saw a notice that collgate toothpaste many variants including total 75ml marked for R13.00<br> I took 2 packs and on payment noticed that a discount was not given so I went and spoke to a manager her response was not that is that that collgate total type the are about 10 different types in store and the notice was clear collgate total 75ml did not read on any limitations on the discount.<br> So all i was offer was a refund pathetic really.<br> I gather that no one wanted to admit to a mistake or did not want to live up to the double the difference policy.<br> So as a customer i don't have much choice but to take it or leave it ??? <br> <br>