I cancelled my IDnotify account by calling the customer service number 888-883-1852.  You can also email them at memberservices@idnotify.com.  They asked for my SSN# but I asked if there was another way to identify me.  The woman then asked for my name and last 4 digits of my SSN.  She then asked for my address.  She said I would receive a deactivate account email in a few days.  I hope this works.  If it doesn't, I will be asking for help on Turbo Tax again.