charity wont stop debiting

I joined unicef as a donated in November 2015 and have donated R80 via debit order in December January and February ,i was advised that at any time wen needing to cancel the donation I could send a email or telephonically cancel .after telephonically cancelling the debit for end of Feb and March the consultant assured me that I would not be debited ,my account is on a minus due to funds being unavailable and them not sticking to the arrangement.Their email address doesn't even work.