Cardekho — Getting Car challans long after sale of car to Car Dekho

I sold my car to Car Dekho Gaadi Store(GIRNAR AUTOMOBILIES PRIVATE LIMITED) on 21.03.2021 and as per agreement (REF. 5E6491)they took responsibility for any liability arising regarding car thereafter.
IN September 2021 I received 2(Two) Challans for traffic violations dated 25.05.2021 and 24.06.2021 for Rs. 500.00 and Rs.2000.00 respectively.

Since the car was sold to Car Dekho on 21.03.2021 I informed them by email on 24.09.2021 for paying the above Challans since the offence was committed well after the sale of car.

They generated ticket no.5831799 and assured me to settle the matter.
But regret to say that I have constantly taken up the matter with them vide my 11 (Eleven ) communications but matter still not resolved and I am getting SMS from traffic police for payment of challans. The reply being received from CAR DEKHO is so vague it seems they are buying time and resolving the matter. Every time they just say that their dedicated team is looking into the matter.
I have raise complaint on their portal also but without response.
They advertise high but my experience is that for solving problems subsequent to sale they are below average.