Received call leave msg state investigation dept FBI regarding tax I ow money to irs they want money put in gift card green dot money load

I received this call via person names as Matt Johnson and claiming to call from Crime Investigating Department from IRS and said there is case against you. Wanted to ask weird questions. What kind of scam is this?

I got call from these number when I picked the phone I was listening so many people were talking but no one was talking to me then I hang up on them . Called back but automated voice mail said its error . I think it's totally Scame