Please help. My 2004 makes a noise on start up. Diagnosed as starter motor so new one fitted £215. Noise much worse after repair so took car straight back to be told it needs ring gear. Got new Hyundai ring gear fitted by independent garage £320. Noise still there, so the garage fitted a second hand starter motor to see if the other one was faulty. Car much better but after just 3 days use its worse again. I want to get the car fixed any ideas what else could be causing this?

Really Need car fixed but can't afford to waste money on wrong diagnosis.

Thanks