What famous woman was buried alive and held for ransom?

I believe you are referring to the Barbara Anne Mackle case around l97l. Ms. Mackle was abducted and placed in a sort of subterranean vault which, was, however equipped with food and ventilation. The crime occured in Florida and the mild climate worked to her advantage. The victim survived and was rescured by the FBI and other police and the abductors were apprehended. I believe a TV movie was done on this hokey kidnap crime. I believe she was a real-estate heiress.