Oh my goodness, I have a phone phobia too. It's a real struggle and very intense. I procrastinate on phone calls...sometimes I even go places in person just to avoid talking over the phone, even though its an inconvenience. I'll drive half an hour to talk to a manager in person to avoid a phone call. Sometimes I do deep, calm breathing...10 breaths, like counting to ten to calm my body down. I rehearse what I'm going to say or write it down. They say desensitization helps...and it does to some degree, but no matter how many times I make a call to my mental health clinic I still get tightness in my chest and rapid heartbeat. Even though I've actually called them hundreds of times. Its one of those things that never entirely goes away. But the more you do it, the more you can tell yourself it will be okay no matter how anxious you feel, because you have enough experiences where everything worked out fine.