Lol at the lads queueing up to throw their fellow punters under the bus. (Subtext is usually - "look at me, I'm a perfect client"
)
What's missing from the OP is whether or not she informed the client that the time slot she's offering is her earliest available time. I assume it is but it's not clearly stated in the OP. If yes, then they're idiots. If not, why are you expecting them to be clairvoyant?
I find the easiest thing when booking escorts is to give them a time - "I'd like an 60 min appointment at 4pm". I used to think that perhaps it would be helpful to give a time range e.g. "I'd like a 60 minute appointment anytime between 2pm and 6pm" but that quickly seems to cause confusion even though you might think it would be more helpful for them to organise their day, space out appointments etc.