Sounds like you're feeling like you're annoying the customer service rep if you're the one calling them, but if they're the one to call you first, you don't get that feeling.
Just know that it is their job and they're being paid to interact and address you. It is their obligation to. A lot of the customers they have to deal with on a daily basis are difficult, hostile and agitating. So if you're not any of those, they are probably grateful and happy to have interacted and serviced you. Any stuttering, awkward pauses or what not, to them, that is something they won't even care or notice. Their main concern is getting what you what you needed, get on with their jobs. They're there to serve you. Remembering this as a fact and keeping this in mind usually is a great help if you have anxiety with customer service reps.
What goes up, will inevitably come back down. Whoever you have to step on when you go up, you will be at their mercy when you go down.
The truth is strictly what the ones in power perceives it to be.
Enjoy any good things, even the little and menial ones, as you will never know what impending distresses could descend upon you in a moment.