Aquí la solución:
To remove the Gmail contact list from the BlackBerry smartphone, please complete the following steps:
On the Home screen of the BlackBerry smartphone, click Options > Advanced Options.
Highlight the <username>@gmail.com [SYNC] service book.
Open the contact list on the BlackBerry smartphone.
Press the Menu key and click Options.
Type RSET in the Contacts options.
A dialog box appears asking the BlackBerry smartphone user to erase the <username>@gmail.com contact list
Click Yes.
Fuente: KB21118