Avis car sale are ********

I bought a car with avis, which was not even checked that it was serviced upon me purchasing which I found out later, it had not been serviced in two years, the gearbox hd already malfunction but they did not report this,they decided too pay for the service but refused too do a major service plus in the service report note on gear box has issues now I'm having trouble with the car plus and motor vantage warranty doesn't want pay too fix the car