Nic With no Answer

My vehicle went for service on 30 January 2019. A weeks later I notified the dealer of a noise coming from the engine when starting every morning. The vehicle was taken on 11 April 2019 to the dealer to overnight so they can diagnose the noise. I received the vehicle and they could not explain the noise. I took it back again on 16 September 2019 and still no resolution. Please assist.