The phrase "unhappy customers" refers to people who are not satisfied or pleased with a product, service, or experience. They may have complaints or negative feedback about their interaction with a company or its offerings. Full definition
Studies show that up to 70 percent of unhappy customers transform into loyal customers if the mistake has been fixed exceeding their expectations. (entrepreneur.com)
The Internet is full of complaints from unhappy customers who found the ride and handling of their vehicles suffered as result of installing run flats. (moneysense.ca)