There is a point where Blizzard considers the case as closed, and will not be reconsidered. This is usually happens when they look into your appeal for a third time, and come to the same conclusion with different people at the office. If they consider your case as closed, any further tickets won't be read or passed on, they'll be instantly cancelled or deleted. Not much you can do anymore, I'm afraid. You can always send an e-mail to CSFeedback, but that's not meant to be used for banned accounts, only to complain if you feel mistreated.