Raising a special levy

On the topic of special levies – can the executive committee decide to raise a special levy for maintenance or improvement work on a building or does the proposal of a special levy have to be taken to a general meeting. In either case i.e. decision by the executive committee or decision by a general meeting, can the decision to raise a special levy be passed by a vote of 75% or more in favour.  

If the decision to raise a special levy is passed by either method above, can unit holders refuse to be bound by the decision – especially in an understandable case of hardship.  What action could then be taken against the unit holder who refuses to pay the special levy?