eFax is total crap. They'll get all of your personal info., then "give you a fax number."
When you decide to use it, they demand a credit card number. This is completely false advertisement. They claim it to be free, in order for you to give up your personal information.
When you receive a fax, they will not relinquish the information to you until you pay them!
I found that out before I ever gave anyone the "fax number" they claimed to have given me.