I serviced my car on Saturday, where all the filters were replaced as well as new oil was put in. The engine had also been flushed. When I start the car, it makes a loud knocking noise that comes from the engine. The more I rev the car, the louder and faster the knocking becomes. I was driving uphill, where my car started to experience loss of power, until it died. The oil light goes on after driving just 500m with the car, even after the service had been done. I have had 3 people tell me that there's an 80%+ chance that it's the oil pump, but I would like for someone to look at the car and give me an estimate of what the cost will be to replace it, or if the problem is because of something else. Thanks.