Why is Amazon asking for my email and last four digits of bank account?

Hi. Long story. And creepy too. I was trying to call amazon seller support to seek assistance for adding customization details. And each time, they were unable to help me (suspiciously clueless) , passed my call to another team who would put me on hold for a few minutes.. now the creepy part.. Then an auto female voice breaks out asking me to keep my email id and last 4 digits of bank account ready. I am getting emails from amazon confirming the interaction. But strangely, each time, they are creating a new case ID. What do you guys think is happening here?