Ok. The manual says that up to four phones can be paired at the same time, maybe you've reached the limit if more phones have been paired in the past and not deleted; therefore not taking a new phone. Try this to delete ALL devices:
1-Press and hold the button with the "speaking face"on the steering wheel, then after about three seconds, turn the ignition key to position 1 and release the button after aproximately 3 seconds. "BLUETOOTH PAIRING" appears on the display or monitor.
2-Press the button again for approx. 10 seconds until you hear a triple accoustic signal.
"PAIRED DEVICES DELETED" appears on the display or monitor.
3-To conclude the deleting process, turn the ignition key to position 0.
All the phones that were originally paired are now deleted.