I don't get the problem.
I stop answering my phone about 3pm each day - if they haven't rung by then, tough shit - they can try me again the next day.
If they ring at any given time and I don't feel like speaking to anyone at that particular time, I don't answer. If they want to get pissed off that I don't answer, tough shit.
If they want to see me same-day and I can't see them on that day (or if I just don't feel like seeing anyone), again, tough shit.
There's only one of me. I have a life to get on with outside of my escorting work. The last-minute-Larrys will have to go see someone else.