Service denial by Girias

Location/place: Nelamangala/bangalore

Name of company/service: Girias/Retail home applaince

I have purchased a samsung ac in Girias Malleshwaram showroom,They have told the installation free & they are demading 500/-for installation ,still after 3 days of purchase they have not installed , when spoke to the branch manager he is telling i cant do without paying you can do whatever you want,so i need the justice to be done after purchasing a goods value of 31000/-