Your litany of problems far exceed the scope of an online forum. Hire an attorney. Enforce the agreement. Take advantage that the other side has a lawyer that has withdrawn.
A notice of non-representation filed after the Final Judgment of Dissoultion of Marriage is generally filed by attorneys alerting you and the Court that their representation has ended. It simply means that they were hired for the divorce case and now the case is done. What it means for you is that if you are going to file a Motion for Contempt or a Supplemental Petition for Modification, you will have to serve your ex and not their old attorney.
This answer is offered for informational purposes only. It is not offered as, and does not constitute, legal advice nor does it constitute an attorney-client relationship