Remember, the 'customer' is always right. [=never argue with a customer]
He is one tough/tricky 'customer'. [=he is a tough/tricky person]
The company has good/poor 'customer' service.
(..) In eight minutes, I am defauIting on Joe's -minute guarantee. Then, not only am I receiving no money for these pizzas... ...but I will lose the customer forever to Pizza Yurt. Look, you are my only hope, all right? You have to make it in time. Peter, you're a nice guy. (..)2004 Spider-Man 2