Karen
The time limit on receiving Contribution Based ESA does not apply while you are in the Support Group and as you appear to have been moved straight into that group from the Assessment Phase you also retain the full 365 days should you be moved out of the SG and into the WRAG.
We can't offer advice about whether you should resign but you should definitely get face to face advice before you do, you may be giving up rights that you may later regret losing.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems