Maruti Suzuki India — vehicle which met with an accident , taken for repair ,not received back after 4 months

I have been using a Maruthi Celario Auto Gear Shift Car, KL-01–BZ– 2688, since November 2016, which was purchased from M/s. Indus Motors Co.Pvt.Ltd, Pattom.The vehicle met with an accident on 26th September 2018 and on the same day it was taken by M/s.Indus Motors to their Vattapara branch, Thiruvananthapuram, Kerala for repair.It is insured with Maruthi Insurance.
I wish to inform you that after nearly four months period the vehicle has not been returned to us.At the time of taking the vehicle, they had said it will take time as spare parts are to be purchased.2 months back when we visited the workshop, they had informed that all spare parts have been received. Whenever we enquire about the vehicle, the reply is that the work is in progress. But the delay is too much. Many times enquiry have been made from Indus Motors Office at Ernakulam regarding the service of the vehicle and feedback and rating of the same.Before getting back the vehicle how can we rate the service?

Please do the needful for getting us back our Vehicle as soon as possible. We have been dealing with M/s.Maruthi company andM/s. Indus Motors Pvt.Ltd since 2005 and our previous experiences have always been excellent.