Учебник английского языка «Survival English»
Culture File 42:
Sometimes you need to complain. It is best to be polite, but firm. You can ask to speak to a manager, but don’t do this unless you have to. It is insulting to the person you are talking to.
When you are in a business situation, you may have to answer complaints. It’s important to answer complaints immediately, and to have a system where people can complain if they are unhappy with a product or a service. It’s worse if the customer doesn’t complain to you, but goes away and tells everyone that your product or service was bad.