Bozhou zhongzhou Buick 4s store. How about after-sales service?

Bozhou Zhongzhou Buick 4s store cannot be guaranteed after sale. Before buying a car, I promised to maintain a navigator for free three times. After buying a car, the navigator directly said no, and the promised three free maintenance were only honored once. Such a company makes people speechless, and there is no even the most basic integrity. Buick can't even guarantee basic after-sales service. No matter how good the car is, who would recommend it to a friend? I strongly protest that 4S stores don't pay attention to honesty.