Bad service

I took my car for 45000km service on 07/10/2020. The following day my car had a irritating sound in the engine. I took the car back 12/10/2020 and i was told that my battery is dead. Now i went to two service stations to change my battery to get rid of this irritating sound, and i was told that my battery is still fine so no need to change and the sound has nothing to do with a battery. I called Group 1 Renault more than enough now, they always say John (service manager) will call me back. I think they created this because they saw that i paid cash for service. I wonder how would the staff feel if what they did to me has done to them.