Carrier Airconditioning & Refrigeration / Carrierindia.com — Issue with Brand new ac

I have bought a brand new 1.5ton Ac, from the day one we were feeling like there is an issue with the Ac with cooling as it can not hold the cooling for a while but as our room was having some air leakage via vents so we thought ok we should give some time and cover the vents and try. After covering the vent also the issue did not resolved so we raised a compliant[protected] there were few tech.persons visited and checked the Ac despite of acknowledging the cooling ac they rae telling ac is good no issues with it but at the same time we have shown them the issue by running 2 hrs the ac and when we turned the ac off it hardly hold the cooling for 5 minutes.

We have mail them but no response.They are trying to ignore the facts.
We have invested almost 40k, our hard Earned money in the Ac.