LG 5 star split A/c 1.5 tons
Cooling is ineffective

I had purchased a 1.5 tons - 5 star rated split a/c model no LSA 5P5VFI . The purchase was done in oct 25 and it was serviced twice after the installation. After the second service which was done in the month of June I find that the cooling is ineffective. Even when the A/C is in jet cool mode, the room temperature is seldom less than 28C. I feel that there is some problem in the machine. Please arrange to attend the problem