You can try to collect all the evidence. Then submit it to the court. Court should accept that evidence of call recordings first. That itself is doubt. IT Act itsself many judges did not study. Usually they will accept the call recording details and transcriptts (verbatim) but they will not consider it. Even video recordings if you have they will accept it but will not consider it as evidence.
You will have to prove her voice is hers your voice is yours etc.
They will go for only one evidence whether she wants to live with you or not.
You instead of wasting time proving all this, getting all such records from telephony company simply purchase divorce by giving one time alimony to wife and save time and yourself from 20 years of self torture. Court cannot give solution to your self created problems of marriage.