Mavis Discount Tire

I took my vehicle to mavis for a loud noise and then they said it was the alternator and I told them it was the pc value and then they changed the alternator and it was still making that sound so then I came back they changed my cover value but it's not my dealer cover value they changed two things on my vehicle that's not the original dealer parts then my engine started overheating and leaking oil everywhere in the engine and I had to go back 3 to 4 times for the same issue