Ett
You really need to get face to face advice from a trained advisor, your situation is obviously complicated and requires sight of the papers involved.
Do an internet search for "welfare advice" with your postcode, town or county.
If your ESA started on 22 September 2012 then you would have been entitled to Contribution Based ESA until 21 September 2013 if you were not placed in the Support Group,
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems