A buyer who is reluctant to change a product or supplier due to higher prices.
Английский Язык - Английский Язык
Определение captive customer в Английский Язык Английский Язык словарь
(Ekonomi) Buyer or user who is reluctant to substitute one product or vendor with another, because of the high cost (in terms of discomfort, effort, and/or money) involved in switching