Are you sure its something you have to talk to him about? Because like you have said he does not answer the phone on the weekends, he probably will not get the message till Monday.
This would be a good opportunity for you take care of things on your own without him. That way when he does contact you you can tell him its already been resolved. If he asks how just say its been taken care of and leave it at that.
Remember to be mysterious. This is also a great way to show your strength to him
