I feel your pain! I worked at a call center for a few years and that was extremely hard and almost quit a few times (plenty of rude customers asking why they would hire someone with a stutter...). I would also freeze up when answering calls and couldn't say anything. The only way I coped with it was changing how I answered the phone, mixed words around to be able to start the phone call. Once I got too comfortable with an opening I would start having a block again and have to change it up! After about a year or so my confidence increased and my stuttering improved a lot. Then I got a promotion to train the new hires to take phone calls and my stuttering improved significantly! With my experience a big part of stuttering when it comes to work is your confidence with the position which takes time to build. One thing that helped me at my current job is to let my co workers know that I stutter and I'm working on it, sometimes it would make me stutter more knowing people can hear me and them not knowing about my stutter if that makes sense. If you are having a rough day or calls I have also informed the people on the phone that I do have a stutter so they aren't thrown off with long pauses. It is a long road good sir but you can do it, I still struggle here and there and have rough days. If you have any other questions or anything let me know.