Always, always, always, practice being super kind. I start by repeating their name back to them "Hi Jane, my name is Anna Felix, how are you today?" Be super patient and super polite, always "yes ma'am", "no sir", "thank you ma'am", "thank you sir". Like my mama always says, "you'll get way more flies with sugar." (Is that how the saying goes?) Allot enough time to these calls, usually around 20 or 30 minutes because they put you on hold a lot to look over things then come back, ask a question then put you on hold again. So, use an abundance of patience and kindness, answer the question only, don't ramble or give any extra information. Let me know how it goes!