Game don't honour their marked prices

On Saturday 19/09/20, I went to Game Rosebank to buy a couple of things, when I stumbled upon demo headphones that were on display. I was attracted and asked why the headphones were marked at the prices they were. I was told by both of the staff that the headphones in question and a bunch of other headphones were demo headphones from Dion Stores. Those headphones passed several hands with no one objecting the price that was stuck on these particular headphones... When I got to the till, I was denied to headphones by the manager, saying it was human error, and when I tried to challenge that I was told , "no sorry it human error, you can see"... What a way to ruin my weekend.... Needless to say the headphones were missing quite a few accessories hence I felt I'd but them for the price advertised