selling cars that not check propley check

I purchased a diahatsu sirion from mma car dealership and from the time I got the the car its only givin problems they took it in to sort it out but still come back with same problem.from the time and I bought it had problem with gearbox,powersteering,discpads and electrical problem and when u phone steve to tell he say it not a brandnew car it a ten year old car and when we wanted to change it before 30day for other car they said they can't when we pick up the car we only givin the car every week to them. they had it more then us frm the time we purchased it. But should take it out to sort out it should work for few days and problems again. So I say there sell **** car to people don't do all the check 100percent before giving they clients.and don't help sort out car. Up till now I am still having problems with car. And when u call steve he say it our problem coz it not a brand new car and he can't help in a bad manner he speaks. I bought the car for my wife.