Got a call from this # today.  Didn't answer and they left no message.  I'm not sure who "HSG" is but they aren't someone I want to talk to.  However, going through my records of blocked numbers, I noticed that "HSG" has called me from other numbers, so here they all are:

4802377937
4802377951
4802377928
4802377950

I added this number to my blocked list.  We'll see if they call from another number now.