Jubille motor's poor service

I bought a car in April 2019, the second hand car gave us it had sign on the dashboard, now again it has another sign. The refuse to fix the problem on the gearbox. jUBILEE Motors is just telling us to fix it our selves cause they can only fix the problem if it was detected in 30 days apart from that its our problem or we must sell the car. I am disappointed at their service