And yet you believe that God is the efficient cause of itself!

Hawking's solution is complete, and describes the observable universe.

You don't like it, for emotional reasons perhaps?, and thus you postulate a completely unobservable and unprovable God who has personal relationships with humans and can even be flattered through prayer into doing things for people, based on no evidence whatsoever.

This is not a "refutation". At best, it's an alternative model that you find more appealing but that requires a considerable amount of extra mechanism - mechanism that can never be observed.