You can try this procedure to delete all phones from the car's ULF system. From the manual:
Deleting Devices
The paired Bluetooth
TM mobile phones can only be deleted as a single group from the ULF control module. The pairing procedure must first be activated, and then the send/receive button on the installed eject-box or the pairing button located at the rear of the center console must again be depressed for an additional 10 seconds after the "Bluetooth Pairing" message is displayed on the radio in order to clear the list of paired devices from the control module and the message "paired devices deleted" is displayed.
Good luck,
Dennis