Hitachi Ac - Unfair Trade practice

I had recently purchased * Hitachi Aircons. I was informed that the installation charge will be around Rs.*** (special offer) and materials cost at actual or market rates. At the time of installation, the technician purchased copper tube and cotton from a local shop (where it costs just Rs.*** per metre) but charged me Rs.**** per meter. As the material is not manufactured by Hitachi nor supplied by them it is not fair to purchase a lower cost and sell to me at more than double the cost.When I said I will purchase the materials and give he said then there will be additional installation charge of RS *** per metre. So in effect while it will only cost me Rs.**** if I purchase the same material from the same shop, the technician is charging me Rs.***** which is unfair and refusing to complete the installation