Tata Motors — Vehicle not delivered as promised

I had booked a Tata Nexon more than 4 months before from SP Vehicles. I was promised by the dealer that the car will be delivered within 4 months.
However when I follow up I get the routine reply from the dealer that they have forwarded the priority list to Tata motors and there is no reply from Tata Motors.
It is extremely unprofessional of Tata Motors not to respond to such email and keep the customer waiting without a deadline.
I had never expected such a dealing from Tata Motors and would never reccomend it to anyone else if there is no proper response.
Kindly let me know the status of the car which I have booked and it's delivery date.

I had also raised a Customer complaint for which also there has been no response so far. Complaint #[protected].

Anticipating a prompt reply.