Who called from 4378871427

Just got about 5 in a row from this number.  Not sure who the heck it is.

unkown caller...does not have answerable service when checking to see who called.

Woman with Russian accent, lots of background noise, like in a call center.  Told a friend recommended me to them, refused to say who (duh), asked if I had experience trading currency.  I ended the call at that point.

Got four calls from this number I answered they said they were the police and would call me back later. Added to block list.

They said I was referred to them to invest