Besides, your permanent crown is not going to fit because by the time the dentist grinds off you temp your tooth will not be the same shape it was when the impression was taken. Optibond is not the material to use to put on temporary...
You should discontinue dealings with any professional who refuses TO TALK TO YOU. Really, you already know that.
No, you should not go back to a dentist who refuses to talk to you on the phone about treament HE did. And a couple of other things - Optibond is not a permanent cement, it is a bonding agent. Optibond is what you use to stick things...