It's not cringy but will damage your professional life if you keep it up. One of the best things you can do as an employee is be a good communicator. Stuttering has nothing to do with this. That said, I feel your pain, as I struggled with phone calls badly early on too. Even at one of my first jobs for an auto shop, I often had to get a taxi to take me back after dropping off a car, and I would walk around and find a street/house number I could say before calling. Or I'd take hours building up the guts to make a phone call for work I needed to. Eventually you're going to have to work through it and get over it. Sucks now but do what's right and it will get easier.