You should find out the reason for change in the survey number.
You ascertain the facts that whether the survey number has been changed by the revenue department from the previous one to the present one and what is the reason.
You can get the information through RTI act too if the revenue department is not answering to your queries.
If your father bought the property around 20 to 30 years ago, why did he get the property registered on his name only in the year 2016?
Your information is contradicting to each other.
Hence you may better clarify the details from the revenue department itself.