I have already gotten 3 calls from this number today, no idea who it is

Got 2 calls from this number, no message, so I called back.  A girl named Jennifer (?) answered with "Hello?"... turns out she was selling a cruise.  I told her I wasn't interested and the call disconnected.  I got a 3rd call from this number that I didn't answer.  I called back (got a simple "hello?" again) asking to be removed from the call list.  She said "no" and hung up.   Incredibly unprofessional...   The way the call connects (slight delay and a clicking sound), it sounds like a Google Voice number.  Who ever she is, she's terrible at her job. I'm sure she'll call back.