I think the ladies can get into trouble with Adultwork if they are deemed to be ignoring emails. Maybe the autoresponse feature gets them off the hook? Personally, Adultwork email is my least favoured option for arranging things but I accept it's often the only way to contact them.
One thing, it's always worth googling them - they often advertise elsewhere or have their own website or Twitter or suchlike and sometimes you'll find a contact number or direct email for them there.