If you're getting free sex then you wouldn't complain if the girl was not up to scratch. You would just take it on the chin and find someone better. However, you're paying for a service provided by a girl. If the service was terrible and I mean very bad (and not where her service ticked all the boxes but she just didn't allow DFK or DATY to the disappointment of the punter) then you have a right to complain to the boss or mamasan or write a negative review. Why be silent in cases of bad service?