When you aren’t able to close your account it is generally due to a pending transaction on your account with one of your linked funding sources. Try to remove all funding sources linked to your account and attempt to close the account again.
Another cause for this could be a linked PayPal card on the account needing to be handled first, such as needing to call PayPal Credit Customer Service to see if that is preventing the account from being closed.
I experienced this a few weeks ago. I’m going to call you again soon. Moreover, they refused to allow me to close my bank accounts because of a “error”. I threatened to call my bank, and that’s when the problem mysteriously disappeared.