WhatsApp booking is the whole reservation done in writing, in one thread, where the hour, the fee and any deposit are set down before she sets out.
No switchboard. No hold music. A thread. You write, a person reads it, and the reply lands in that same thread; a crowded evening can slow it, and nothing is fixed until it lands.
Put five facts in it. The technique, or simply B2B. The length. The hour, or the word now. The address, or at least the part of town and whether it is a hotel. Whether you have booked here before. A message carrying all five rarely needs a second exchange.
Acceptance, or another hour if yours is taken. The total fee. Where a deposit applies, its exact figure and the payment details, written in that thread. Then the timing: forty to sixty minutes for a booking wanted now, or the agreed start for a later one.
A thread is a ledger. The price, the half, the address and every change of plan sit there under a timestamp, and both sides can scroll back through them. Nobody mishears a room number. Nobody remembers a figure differently once she is at the door.
Payment details come from the confirmed thread you booked in, and from nowhere else, and only once the hour is settled there. A message asking for money before the yes, or from outside that thread under any number or name, did not come from this house. Ignore it, and mention it in the thread you booked in.
The sequence from first message to knock is on the booking page. Anyone new to the house may want the first-timers guide as well.