I'm going to tell a customer service rep not to interrupt me
Why would you say that to a customer service representative?
My account is in good standing. They don't need to keep interrupting me.
Your account status is irrelevant, you should be polite on a customer service call. Being rude on a call will upset the service rep.
The customer service rep is awful. I don't need to be polite.
Even if you don't think the person is good at their job, that's no reason to be rude to them. Being in customer service is very difficult, so you should treat them with respect.