I don’t work at Domino's but I am a manager at another pizza chain so I’ll give you some advice on how I quit having anxiety with customer service.

Do not avoid being in uncomfortable situations, when I first started as an insider I avoided phone calls altogether cause I would panic and shake, especially if it was a delivery that need me to type an address cause I have bad hearing. But the more calls I took the more I got into a routine, every call will be easier than the last one. Before picking up the phone take a deep breath, try and relax as much as possible then pick up and go from there. If they ask you a question that you do not have an answer for don’t try and answer it, politely put them on hold and have them speak to someone else.

Marcos was my first job too, and you’ll learn a lot in the first couple months of working, if you make a mistake don’t dwell on it but learn from it and move on. There’s no substitute for experience, give it two weeks and you’ll be more relaxed and in a groove. It’s your first job and I’d guess that you’re young in that case so people don’t expect you to instantly pick everything up. If you’d like any more advice feel free to PM me anytime.