CyanogenMod delete WhisperPush account
I have an answer for you.
Cyanogenmod should implement a simple solution!
The fix can be found on the final post of this page:

http://forum.cyanogenmod.com/topic/87482-critical-flaw-in-whisperpush/

You'll need android studio installed on your PC to use "adb" in terminal/command-line.



These are the steps that are suggested on that site:


  You could try to unregister manually:

pc:$ adb shell
phone:$ su # (enable root for ADB first)
phone:$ cat /data/user/0/org.whispersystems.whisperpush/shared_prefs org.whispersystems.whisperpush_preferences.xml
# take note of pref_push_password and pref_registered_number
pc:$ curl -v -X DELETE --basic --user $pref_registered_number:$pref_push_password https://whisperpush.cyanogenmod.org/v1/accounts/gcm/
# add -k to skip the certificate warning

  
  The HTTP response code should be 204.


Source: http://forum.cyanogenmod.com/topic/87169-disabling-whisperpush/#entry448596