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.
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.
You can report this fraudulent activity to your local post office or contact the United States Postal Inspection Service online or by telephone. Provide them with any evidence you have of the attempted address change, such as emails or letters. They will investigate the matter.
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.
Mail from the U.S. Postal Service comes with a guarantee of privacy. If a third party opens mail intended for someone else without the addressee's permission, that person has committed a crime punishable by law. No such privacy exists in e-mail.