do i need a real estate attorney?

i purchased property though owner finance several years ago. the deed was put in my name. the person i purchased the property died and the wife told me the property was paid in full and signed a release for at the title office. now the kids of the man i purchased the property from say that i dont have a clear title and i owe them money. so if the title wasnt clear or i owe money wouldnt i have been notified by the title company?