Its usually up to the girl which customer they see.
A lot of time they will book a regular on WeChat or whatever as well they will usually take whoever there first.
But yes the mamas and papasan do lie and trybto rip people off.
No you are not. Annoys me a little when I have made a booking at an establishment only to be told that the current customer has extended an hour and the booking you made has been consigned to the trash bin, however it's part of the deal so I just go with the flow, what's the point of making a scene? At the end of the day it reflects poorly on you not on anyone else.
On the other hand WRT to mamasan/papasan doing the girl/room shuffle, does anyone think about how many bookings are no shows and don't have the courtesy to let the establishment know - I'd bet it would be a regular thing. Can you blame them if they don't know you from a bar of soap when they prioritise high value customers?
Reading some of the responses to this thread, there seems to be amongst some, the idea that just because you have splashed some cash and given "gifts" to a lady there is some implied type of ownership/debt of the lady. What fantasy land are you living in? I pity both you and the ladies you spend time with, what sort of person gives someone a "gift" expecting something in return? Oh thats right a manipulative, exploitative and controlling arsehole.