Unexplained odor
Who do you call to find out what an odor is. Could it be a gas from a drain in a pedicure room?

The most efficient first step is to identify the type of smell - sewer smell would mean you call a plumber. Dead mouse would take an exterminator. Go around the shop early in the day when your nose isn't full of soap and acetone smells, even if you have to crawl around under things. If I had to guess, I'd call a plumber first.

Who are you to this, a customer, a worker, the owner ?

But normally you smell and find out where the odor is coming from. Then call the correct maintenance person