Dave I would have been thinking of dumping her anyway after the second phone call.
and to be honest I would'nt have given her a penny back, she's probably been bad mouthing you anyway, to the other wc she must have called in.
I use a three strikes and your out motto, if a paticular customer P***es me off, they get a strike against there name, three strikes and they are off my list, we don't need moaners, and there are plenty of nicer people out there screaming out for a good wc.
Thats just given me an Idea for another thread, keep your chin up Dave.