New AC and New Sound

Today I had a new compressor installed. When I first turned on the car and turned on the AC to about midway I could hear a faint hum, which sounded different to the sound my ac would make before it had broken. I went back inside the shop in which I had it fixed at and told someone. They said they could kinda hear what I heard, but they said it almost sounded normal. And that if it persisted then to come back in a couple days.
When the AC is on and I accelerate and decelerate the car makes a loud humming sound the first time I drove it home. I will definetly be taking it back, but wanted to ask for some insight first! Thank you