I believe this to be a scam. This supposed caller from "financial affairs" left a message to call her at the number posted above but called from # 7708186306, which has been reported as a scam on this same site. Instead of a male investigator Johnston calling it's a female named Monica Sellas.
Yesterday I blocked a Georgia # 770-818-6306 that was stating he was some investigator. Today I get this new number that called stating it was a Monica Sellars from "Financial Affairs" and that I am supposed to recieve mail to take of the matter. They never say my name so I think this has to be a scam. I am blocking this number as well.