acs inc. they have sent me threatening e-mails and left threatening voice mails periodically for almost 3 years. Internet

These "people" have represented themselves as legal officers, law enforcement, FBI agents (?!), and financial counselors over the last 3 years or so.  They can evidently clone phone numbers at will, so as to trick me into answering their calls, thinking they are someone I actually may wish to talk to.  I have been given to understand that they may be offshore; their command of English, syntax, and moral/ethical context would tend to support this theory.  I simply want them to disappear. This whole episode/nightmare has affected my telephone habits, my feelings towards foreigners - even my friendships.