Who called from 7075952550

Has called me twice this week, nothing to be heard on the other end.

I called back, the voicemail system said the mailbox was full.

WTH? I picked it up said hello 3 times and they hung up.

They called two times today and the third time I finally picked up and said hello but no one was on the other line so I hung up.

Called me twice at 9 PM and hung up. Tried calling back but can't get through. On my [***] list

They have been calling several times over the past few days. I usually don't answer numbers I don't know, but I wanted them to stop calling so I finally answered this morning.  They said that it was "MMS" (I think - they said it pretty quickly) calling for a public opinion survey.  I politely requested that they remove me from their list.  Hopefully, it will work.