Pick up the phone during normal business hours, M-F. Phone numbers vary by region. Do a Google search for "Contact Adobe."
Keep in mind, you cannot have it both ways. You cancelled your plan. That means there is nothing more to discuss. Your plan no longer exists. 50% early cancellation fees are the terms you agreed to when you joined.
Nancy O'Shea, Adobe Product User & Community Professional Alt-Web Design & Publishing ~ Web : Print : Graphics : Media