The email you entered was invalid. When you enter an invalid email address, you immediately forfeit your fax number. The reason for this is that fax numbers have a cost to maintain. If the email entered is not valid then we assume that the user is not really intending to use the fax account and therefore we remove the fax number from that account.
If you entered your email incorrectly follow the instructions at "I am having trouble with my password, what do I do?".