AC his was probably not installed

Hi my name is Pranab I am from Hyderabad few days back I purchased Micromax AC after 3 months its not working I am completed 2 you Micromax service centre he was come and repaired AC what is the problem when I ask he said properly not installed your AC that's why again I am feeling the gas but 0 but never second time you field gas it's called old so so after he repaired my AC it's not properly working Micromax also not responding please clear my I AC problem thank you