Funeral cover lost

My parents took out a funeral policy 01 06 1978 Policy Number ********** 980 as you can imagine back then it was just a book and your receipt was pasted in this book. over the years this policy is paid up and when my dad went to the Wyberg branch yesterday he was informed that he does not have a policy and they cannot trace his policy at all. This is unacceptable because April 2016 a Lady was able to find my dads contract and said we must E mual ********** with an update on my parents address and proof of the book which I did. I need something in writing that states my parents have a policy as this is *****, my parents paid there policy for years now you refuse to give them proof what if anything happens to my parents?