Drive belt and accessory pulley repair

What is your question?

I had my drive belt and accessory assembly replaced but my Mechanic who is getting older Hadissues while repairing it. Anyway, his wife said it took 45 minutes for him With diagnostics. Said belt was located Behind wheel? My issue is the car seems to still have a whirling noise, not as loud, but car sounds different then it used to. You notice it when car is idle. Since I left him a message and he's not responding, I wasn't sure if I need to have another mechanic look at it or even be concerned with it at all the car is running fine. My other question is, would the belt be misaligned or installed wrong if it's making this noise.