Sold me a damaged car

I bought a second hand car from them and 7 days after the purchase oil was leaking , the sump was patched which was leaking ,which we did report to crazy cars,and had no feedback ,four months later the gear box packed up ,the car was than towed to an Rmi approved dealer ,we contacted crazy cars ,and the advise that the mechanic at the RMI strip the car and find out the fault .After the RMI Mechanic advise the gear box needed to be replaced crazy cars advise that it will not be on there cost and I need to pay to have the car sorted out. How was the car COR approved? I am highly disappoint with the manner I was treated ,I do not advise anyone to buy a car ,from crazy car ..waste of money