Tata Motors — tata motors chandigarh false information provided/sold vehicle overpriced/harassing for refund

I purchased a delivery vehicle ace tata zip from cmpl motors, industrial area, phase 1, chandigarh on april 23rd, 2017 (Sunday).
First of all what price these people told me for the vehicle and the actual billing done is totally different.
These people billed me extra. Also, they delivered me vehicle which had a dent of right side (Driver side) bumper. When i asked them to change they said that it is a minor thing and that other vehicle is not available and promised me some compensation for the same (Which i never received). The branch head was himself present and promised to compensate as much as possible.
I was handed the vehicle which had no accessories (Tool box etc), no wheel cups. They took down payment and asked me to take vehicle and that the day being sunday they will bill me next day which was monday.
I agreed and took the delivery of vehicle.
After around 15-20 days, after many follow ups and calls they provided me with the bill and other documents so that i can register my vehicle with registering authority.
I was shocked on receiving the invoice. The price mentioned in it and what i was verbally told at the time of purchasing was totally different. I asked them to do the changes and bill me what i was told. But they said this is what i was told. But after much persuasion they agreed that they will refund the extra money.
But its almost 3 months now and they have not made refund. Every time i call or personally visit them, they say that the signing authority/branch manager is not available for signing the cheques.
I want you to kindly take action against these people and get my extra money refunded.
I am being harassed by them for the last 3 months now.