Volkswagen India — time of service in apple auto, whitefield

We gave our car for regular service on 18th january 2018, in apple auto, whitefield. This is third time our ac was not working. It occurred first in may 2017. The service team was unable to find any resolution, they took nearly 15 days. They don't tell the customer about the progress.

This time the team told it will take 1 day, but on calling they extend it to monday, then calling on wednesday the team kept the phone on hold and then didnt picked.
We needed the car urgently.
I am fed up with the after sales service and its pathetic.

I want a strict action against them.