Land document missing and incorrect survey no

Hello, I have a question let me know how could we handle this? 1. Land document missing and my dad passed away. 2. Noticed from the photocopy that one of the survey subdivision number they mentioned incorrectly. The person who sold the property also died as it was purchased around 20 years ago. I don’t want to go to their kids as they are not good and I am thinking they might cause problems. How could we handle this and get a new corrected document?