Tata Motors — Issue with my Tata Hexa

I own and Tata Hexa XE variant which was purchased in the year 2018, I have got my extended warranty, 2 months ago I had an issues with my A/C, when the vehicle is in idling the chillness will not be there whereas while the vehicle is running the chillness will be there, for this complaint i have given my car to Lakshmi Tata in the month of June and till date my vehicle is lying there and whenever I call up them iam being informed that spare is not available in Tata Motors and they are not even aware about when they will receive it, due to which I have called Mr.Kashyap who is the service manager from Tata end and escalated the issue, but from then on he is not even attending the call. Why Tata is appointing such kind of people who doesn't even care to reply for an customer who have trusted Tata and taken the flagship vehicle of their company. Dear Tat motors kindly resolve my issue on priority.

Vehicle No: TN05BR9897
MOBILE NO: [protected]