CHARITY SCAMMERS USING VARIOUS MADE UP CHARITY NAMES AS LISTED ON COMPLAINT SITES. MAKES REPEAT PHONE CALLS FROM VARIOUS PHONE NUMBERS. TARGETS TOP EXECUTIVES AT BUSINESSES.

These people are complete idiots who refuse to answer any question. They will not tell you where their company is located or give the company EIN. They refuse to tell you what their company does. They refuse to tell you who their supervisor is or give a contact information for that person. They refuse to give a call back number. Their M.O. is to get the person on the phone that they feel has the money to target them for a charity scam. They call back repeatedly many times a day, several times a day for weeks on end. They have a couple different people calling to try to fool you, but they were dumb enough to claim to be from the same fake charity which is how we learned about them.  When they know you are someone who has blocked them from their target, they will either hang up or else lie and claim they misdialed. They want to get some other person on the phone who will allow them to speak to their target. They do not want to leave a voicemail.  They will call your switchboard from two or more phone numbers at once, hoping to get a different operator while they distract you, the person who hangs up on them.
Here are numbers they have used, but they probably have many more:
301-298-1483
301-298-1897
301-298-1899
301-298-1964
301-358-5124
240-204-9313
240-204-9314
240-204-9315