You are either:Your daughter no longer qualifies for support. You may write up your own ammendment and file it with the courts. You may also file a consent motion to change child support form 15D http://www.ontariocourtforms.on.ca/forms/family/15d/FLR-15D-Apr08-fil-EN.doc .
- Misunderstanding what all of these "legal persons" have told you, or
- Twisting what these "legal persons" have told you to justify your emotional need to take your ex to court.
By filing either of these you end support without having to go in front of a judge. You do not have to go in front of a judge. YOU COULD HAVE SETTLED OUT OF COURT AND JUST FILED THE CHANGE.
Moreover, your eldest daughter didn't move with you. You obviously knew this before your ex did. The onus was on you, legally, to inform your ex of the material change and to initiate the proper change to support immediately.
Why didn't you do that? Did you pay him back extra support amount that you had been receiving fraudulently?