There was a call from my home just now, and the caller ID didn't show. It says there is my mail in the post office. I asked him to open it for me and said, I have one.

This is just a scam. It's all about postal services, police and courts. It's all to divert you, and a few scammers play a dual role.

The purpose is fraud.

The subsequent plot is that you are suspected of committing a crime. In order to clear your guilt, you need to verify the legitimacy of your funds, let you operate at the ATM, and then you transfer the money to the liar.