Can I Move Consumer Forum / Court

I sold my 1st. Hand Car to a Party (who buy & sell different Cars) at a negotiated price of Rs. 'X' amount in November 2018 in Kolkata. Now, while handing over my car to them they gave me (X - y) amount. Where 'y' is the amount they are keeping with them till they sell my car to another. And this 'y' amount will be handed over to me at the time of my physical presence at a Motor Vehicle Office - where the Registration of concerned Car will be done with the new buyer. They also gave me the above condition in writing. They also verbally confirmed that they will sell the car as quick as possible but latest by January 2019. They also contended that more the delay; less will be the price (mainly considering Depreciation). Now, as quite considerable time been elapsed & as I can not wait for Indefinite period - confirmation needed if my case is suitable for taking to concerned Consumer Forum / Court. If so; then I will move through Professional and Competent Advocate.