I brought a car toda...

I brought a car today around 1... on my way to offi e the oil light starts to flash ...showing there a fault... knowing abit about car ... its shows the oil pump is faulty also signs of a bearing knock... called salesman n he says hell get back to me ... manaager says the car is AS IS... so they dnt want to refund it... after driving it for 12-15km showing this issue.... this isnt fair as this is my savings i used to buy the vehicle.... wht must be done... as they told me as is...