Hey Bro. Just wanted to say your story sounds alot like mine. I'm 30 from New Zealand. I've worked at the same job for about 12 years and there are people who I have worked with the whole time who have no idea I stutter because generally face to face I don't have too many problems. I've built up a phone avoidance and right now I sound alot like what your describing. When I first started working in my late teens my actual job was to answer the phone, that's all I did all day. It never occured to me that something might go wrong. Then when bad stuff started happening on the phone bad situations, bad instances with my stutter, it shattered my confidence it's got to the point where I am hopeless on the phone. I've started seeing a psychologist recently (I'm only a few sessions in) so I don't have alot to give you as far as tips and hints. But as I said, at one point I was really good. Avoiding won't get you anywhere, it will only screw things up worse for you long term, learn from my mistakes. The more you do it, the more comfortable you will become, I know it seems like hell but you will get better. Best of luck man, just know that there are others out there in your situation and you are not alone.