Poor workshop service

Took my car in for an annual service, requesting especially to attend to the "knocking" noise in the engine compartment when going over bumps. On return of the vehicle there was nothing wrong to be found, exhaust leak to be attended to by the client. When I took the car in to Supa Quick Witkoppen, for the exhaust issue, there was nothing to be found wrong with the exhaust. They found that the front stabilizer links and front shocks were worn and had to be replaced, and the top right engine mounting was worn and needed to be replaced? This work was carried out. Knocking noise went away!!!!!!! Why was this not picked up at the Hyundai Woodmead Service?