This sounds exactly like the kind of crap they pull trying to intimidate you while at the same time trying to make you appear to be a nut if you report it to anyone.
They don't care if you know you are being followed, your phone is being tapped, they are reading your mail, etc. because that is the point, they want you to know. You just don't know who it is.
That's what J. Edgar Hoover did to his best agent, Melvin Purvis, for getting too famous (he took down many bold gunsels, including Dillinger). Hoover wanted all the publicity to go back to the agency (him) and all his employees to be anonymous and faceless. The newspapers wanted a hero, and they destroyed Purvis when they lionized him.
Hoover fired Purvis, then persecuted him for years, bugging him and having agents call him up anonymously and giving him menacing messages. Purvis eventually committed suicide, which was what Hoover was apparently after. "The coward's way out" -- blackening Purvis for all time.
This sounds more like some juvenile hacker living in his mom’s basement eating pizza and drinking Monster................
Reynolds wrap is on sale today...