I don’t think you need a lawyer for this. A locksmith, perhaps.
The chair has given you evidence in writing and by her actions of her inability or unwillingness to do her job as defined by section 37 of the Act (below) as well as her disdain for decent behaviour in her determination to further her and only her interests.
Ask your committee to remove her as chair and if she continues to act up, either call a general meeting or apply to NCAT to have her removed from the committee.
If the rest of the committee refuses to support you, apply for mediation then orders at NCAT under section 238 to get orders to have the chair and her cronies removed.
37 DUTY OF MEMBERS OF STRATA COMMITTE
It is the duty of each member of a strata committee of an owners corporation to carry out his or her functions for the benefit, so far as practicable, of the owners corporation and with due care and diligence.
238 ORDERS RELATING TO STRATA COMMITTEE AND OFFICERS
(1) The Tribunal may, on its own motion or on application by an interested person, make any of the following orders:
(a) an order removing a person from a strata committee,
(b) an order prohibiting a strata committee from determining a specified matter and requiring the matter to be determined by resolution of the owners corporation,
(c) an order removing one or more of the officers of an owners corporation from office and from the strata committee.
(2) Without limiting the grounds on which the Tribunal may order the removal from office of a person, the Tribunal may remove a person if it is satisfied that the person has:
(a) failed to comply with this Act or the regulations or the by-laws of the strata scheme, or
(b) failed to exercise due care and diligence, or engaged in serious misconduct, while holding the office.