Healthcare worker

Healthcare worker I work in a clinic where I have to call out patient names. One thing that helps me from stuttering is saying , for (insert name). I just can’t say the name straight out. If I feel a block coming on sometimes I just say last name. I am getting burnt out/ frustrated because every once in blue moon there are patients that “don’t understand me” and sets me back. For example, called a patient,”for lisa”. Apparently she didn’t understand me and I had to call her cell and she kept lecturing me on how it’s wrong.She had hearing problems but she kept blaming me... I honestly get anxiety about this and on top of healthcare being exhausting always taking the blame/being the patients punching bag