Advertizes one price, charges a higher price

I just tried to order a pizza from Bella Pizza in Lakeside. I looked at their online menu, phoned through and place my order. The website quoted the price of the Pizza to be R66.50. However, over the phone they charged me R71 something. When I asked why there was a difference, I was told that the website was incorrect and that the price remained the same. They had also charged me the incorrect R71 something on a different occasion and I had not noticed. As far as I am concerned, that is false advertising and it is illegal.