Question about Title issue

[Jon Rood]

I am trying to buy a lot that adjoins me, and there is issue with the title. It’s complicated so try to follow me: 1980 property was willed to by partition Feed to family. Multiple heirs. I have all located and have a contract with them. 1996 MAN A sold this property to LLCx With a quit claim deed. 1998 LLC X sold to MAN B with general warranty deed. 2000 MAN B sold to MAN C with general warranty deed. Tax office shows MAN C as current owner. Family says original quit claim deed is fraudulent. So does that invalidate other transactions ? Best way to clear Title ?