Wanted: one clue-by-four

Here's a conversation I don't want to have again.

Me: "I need to schedule an appointment."
Doc: "Leave me a voicemail and I'll call you back."
Me: "I don't have a phone where you can call me back."
Doc: "I need a phone number where I can contact you."
Me: "...I wish I had one. Still can't help you."

Two days later...

Me: "I need to schedule an appointment with Doc."
Receptionist: "You need to leave a voicemail."
Me: "I can leave a voicemail, but Doc won't be able to call me back."
Receptionist: "Try us again in two hours."

Two hours later...

Receptionist: "Doc left me some possible appointment times."
Me: "I'll take the one that's not before dawn."
Receptionist: "Great. I'll let Doc know. I'll call you if there's a problem."
Me: "O...kay?"

One week later...

Receptionist: "There was a problem and we couldn't reach you. You need to reschedule."
Me: "How will we do that?"
Receptionist: "Leave Doc a voicemail, and you'll get a call back."
Me: "..."
Receptionist: "...Oh."
Me: "Can Doc send me an email?"
Receptionist: "Oh, no, the doctors can't do that. Privacy blah blah blah."
Me: "Well, how else is this going to work?"
Receptionist: "I... don't know. I guess I can take your email."

Two days later...

Doc (email): "I don't usually do email. Call my office for an appointment. I really need a contact number for you."
Me: "...Would you like to buy me a phone?"