How did the chair get rid of you? Who is a councillor is not for the chair to decide, that's for the public to decide.
How best to tackle it depends on what outcome you want. You have not been clear on this. From what i can see you no longer wish to be a part of the council and there is no police investigation into you. Maybe you just walk away and leave them to it, leave the drama behind and get on with your life.
However if you feel the actions of an elected councillor fall below the standards expected of them, and you feel they should be held to account for this, then your only real option is to submit a complaint to the monitoring officer. Don't expect the monitoring officer to deliver the outcome you wish, they rarely do.