The most important thing to relay to the interviewer is that you are going to handle the situation calmly. Raising your voice to match the patient won't get you anywhere...but in trouble. Calmly listen to the patients concern, allow her to point out what she feels is wrong and ask how you can assist with the situation. Let the interviewer know that you want to take the time to pull her up in the system and verify that you have all of her insurance information correct. We are all human and her information could have been entered incorrectly at one time resulting in her being billed incorrectly. Let the interviewer know that you would consult with the appropriate staff for a second set of eyes if needed. If you realize the investigative work will take more time than expected take the patients name and number down and give them a time you will contact them with more information.