Who called from 2132211005

Received two calls from this number today on my cell. The voice messages were unclear both times.

Rcv'd call from this number @ 6:30am-no msg left.  Caller id name shows all one word "serviceprovider".  My no. is on the dnc list.

These people keep calling almost everyday. They do not leave a message.
I don't want these callers calling anymore.

Just called my work number AGAIN (a government office with a number on the do not call list).  Display just shows the phone number & they never leave a message.

2 more calls today from this number. No message left. Not sure what they want from me.
My number is on the Do-Not-Call registry. How do I report these guys?