If you are seriously considering lodging a complaint against her, pay it. Your position will be undermined if you haven't paid her. If there is an investigation for possible disciplinary action against her you don't want to come across as petty or vindictive. You want to seem like what you are: a client suffering from the effects of trauma who was trying to seek help and treated in a very brusque, unprofessional, incompetent manner. Nothing should cloud that truth. Who knows, the disciplinary body might even find that she should refund you or pay for some portion of your future therapy (maybe that's excessively optimistic!) but leave that to them.