The only good thing about someone haggling, is you can just hang up and hopefully they don't bother calling you back.
Now I could understand if a client was to say how long can you spend with me for €X where X is a minimum of €500, based on most girls are in the region of €200 an hour, but once they get an answer accept it or move on.
Maybe escorts need to start using premium rate numbers for taking bookings, would keep the calls short and sweet.