Netsar never disclose the truth about their contract

I bought a car on the 27th August 2022 and I had to return it on the 10th of September 2022, 2 weeks after the purchase because it had a factory faulty. I called netstar countless about the return of the car and asked them to cancel the contract they then demanded money from me and said that I should pay the account for 36 months of which they never said anything about when I signed the contract. Even today they keep on harrassing me with countless calls and trying to debit money from my account.