For the future, get PO Box address that works as a regular address (UPS offers this for example), and use it with all the banks and literally everywhere - anyone may get hacked and leak your address...
I prefer a virtual mailbox (like iPostal1). You can view your mail from anywhere and choose to have individual mail sent to you anywhere in the world. PO box is not convenient.
I did not find anything about the security of scanned documents or how they are destroyed on the iPostal1 website. Have you inquired about how they handle their digital document security?