Hi bick,
Occasionally, phone manufacturers will release software updates. These updates can sometimes cause the pairing to be lost, and you may have difficulties when trying to pair your phone. Please try to delete the update from the vehicle's history and from your phone and try to pair again. If this does not work, we will be happy to contact your dealership for this concern. Please send us a private message in reference to this thread if the extra help is needed.
Kristen A.
GM Customer Care