The common term is a mail thief.
No, keeping someone else's mail is an offense with the US Postal Service.
Of course it is. If someone filed your taxes for you, contact the IRS. If someone stole a check from your mail contact the Postal Inspection Service. If someone stole money from your bank account and/or your home, contact the bank and local law enforcement.
If you receive mail for someone who does not live at your address, you should contact the postal service or the sender of the mail to inform them of the situation.
Yes, you can mail a check to someone by writing their name on the payee line, filling in the amount, and sending it through the postal service.
There is no law that you must open mail posted to you. But, if you are receiving mail on someone else's behalf or otherwise, you may not open their mail.
Yes, it is a federal offense (violation of United States Postal Regulations) to interfere with the delivery of someone else's mail.
Try: a mailman, or mail carrier, or postman, or postal carrier.
Contact your local post office. They may refer you to a postal inspector.
There is insufficient information disclosed in the question to give a complete answer. Anything unlawful having to do with your mail, report it to the your local PostMaster and/or the US Postal Inspection Service.
Royal mail is the UK government owned mail service. They deliver packages and envelopes. The US version is the United States Postal Service.
From what I understand there is no specific phobia for people who are afraid of mail. Most just call it Mail Phobia...
The US postal system uses addresses to make sure the mail is delivered correctly. If you don't provide your postal address then you will not get any mail that someone wants to send you. Unlike an email address which is short, postal addresses include much more information about you including your full name and the street, city, state, and zip code.