Tom, you can login to your account from the website and on the Summary Page there is a link next to the fax number labelled "Disconnect". When you click on the link it will disconnect the number and no more faxes will be received. The link will change to "Re-Connect" when you are ready to have the fax number active again.
Tom Cook
I would like to be able to "turn off my fax machine" on SRFAX just like I could turn off my old fax machine when I wanted to.