I totally relate to this. For years I would avoid scheduling appointments of all kinds: doctor, dentist, car maintenance, dinner reservations that couldn't be made online. It's a long list! If I needed the appointment badly enough I would actually drive to their location and slide my driver license across the counter to give them my name and address. Jesus what a hassle. These days I just tell myself "screw it, yeah I'm a stutterer, so what?", make the friggin call, stumble through, and get on with my life. Best wishes to you.