Who called from 2027820891

Unwanted calls -- from three numbers, all with the same area code and prefix and all from the same originator (according to my "caller ID -- "DITCO DTSW":
202-782-0891
202-782-2257
202-782-2276

No one answers and calling the numbers just results is endless ringing.  

So far, these just come during the day.

I dialed *67 (to block my number) and called the number back. This is the appointment line for Dewitt Hospital on Ft. Belvoir, Va that is automated to confirm appointments.  You can select the option to report a wrong number, or confirm your appointment.

The call I received had a caller ID of "DITCO DTSW" but was from a 703 exchange. It's a US line for contractors working in the Middle East.

I keep getting the same call but from an Arlington VA address.

Who is DITCO DTSW.  They have called 4 times is this now harrassing.