Non functioning of brand new volts 2 ton split AC

SBI cheque (030099)was issued in favour of Khosla Electronics,Chinsurah on 9.5.16 for purchase of 2 ton voltas split AC. The model SAC 245 ZYE was installed on 22.5.16.Since then it cannot cool the room and is producing a loud irritating noise. On complaining, Khosla Electronics sent servicemen who asserted that the AC was okay even before they stepped into the room where the AC was installed. It was very clear that they had been taught to do so in order to avoid responsibility. On 30.5.16 service engineer from voltas arrived after repeated calls and arguments. He admitted that there was no cooling and the loud noise was irritating but kept on saying that he would report that technically the machine was cooling as per their standard testing. Now this is the height of contradiction!!!This makes me doubt the competency of the service engineer .They wanted to refill the gas but I did not allow because it was a brand new AC. My request complaint is 16053007617. I regret choosing Voltas because my other Samsung AC is working perfectly for over 8 years.Please help me to get rid of this problem in this blistering heat. Voltas should value its brand name.