Don't know if this is going to be of any use, fbg
https://www.facebook.com/invite_history.php
In the text at the top of the page (Should look like this)
The contacts listed here include the information you've imported or synced to Facebook. To remove a contact, select it and press "Delete Selected". You can also remove all your imported contacts. Only you can see your contacts, but this info may be used to make friend suggestions for you and others.
There's a link in the text
remove all your imported contacts