Game not honoring there deals

I went to purchase a special from Game that was advertised in the newspaper and got to the store only for them to tell me that it was a print mistake and the price advertised was R199 for 2 iphones 6's and the manager of the branch in kenilworth center mall game told me that they have a poster up in his store apologizing for the mistake and the correct price is R399 for that special. I told him that i had a photo proof of the special and he said it does not matter and i need to deal with head office but refused to honor my request.