General Motors - Chevrolet Spark — Gold coin not provided

My brother Rakesh Singh has purchased one Spark car (UK 04H 2240) from dealer Nobel Motors in Haldwani, Uttaranchal. He has purchased the car in first week of October. The gold coin which was part of offer was not provided by the dealer stating non availability of gold coins. Later after several follow-ups the dealer told that there is shortage of gold coins and they will refund Rs. 1800 against the gold coin. But the dealer is now not even giving us Rs.1800 in lieu of gold coin. I have registered a telephonic complaint with GM Customer Care on 23rd December but no action has been taken from your side as I have still not received the money. The complaint no. is 16021. I followed up with customer care on 8th January also but there was no satisfactory answer from their side. I wrote a mail on 8th January and got reply that it will be resolved soon but is still not done.