Is Recording Phone Call Coversation an Offence?

I had filed divorce on grounds of mental cruelty and disclosed this to my wife over a phone call. She was staying at her father's home then. I have a phone call recording of this. Immediately i.e. on the very next day she went to local police station (Women Cell) and initiated a false 498A against me. The FIR was registered on the next date of my phone call to my wife. I was informed by a local constable that my wife along with her father was talking to the Inspector and I was asked to talk to the Inspector. I did (again on a phone call) and have a recorded conversation. On the phone, I informed the inspector that: A. I have already filed for divorce in the local family court. B. I had informed about the same to my wife a day ago after which she went to the police on the next day. Surprisingly none of these 2 facts were documented in Final Report by the Investigating Officer. A fake case has now been registered against me and I am made to travel long distance to another state to prove my innocence. As a matter of fact, neither my wife nor the police were intimated before recording the phone call conversation. In an effort to prove my innocence, I have the below questions: 1. Shouldn't the information given to my wife and police in point A and B above should be a part of Final Report? 2. Am I within my rights to submit a CD with the recorded phone conversation with my wife? 3. Is it illegal or an offence to record a phone call conversation with spouse under the IT Act or any other law active in India? 4. Is it illegal and offence under any prevailing law to record a phone call conversation with police - especially the investigating officer who is supposed to investigate a matter where one is accused? 5. What steps can I take to prove beyond reasonable doubt that the false dowry case was filed with an ulterior motive to harass me? 6. Are there any counter cases I can file against the IO for not investigating the matter and not putting in the information I gave to IO on record (for which I have a recorded proof)?