Forensic Investigation of Audio Proof

Hi All I have put a divorce case against my Wife on cruelty basis. To support my case i have submitted some audio recordings . These are audio records of all calls done by my wife which were saved in her phone. Although I have all audio files, the original device (smartphone) is with my wife and my wife is denied the voice. Since I am paying huge maintenance and audio records can prove cruel behavior of my wife. I wanted to initiate forensic proceedings so that court considers them for my case and I have below queries 1) How to request court to provide voice samples of my wife and in-laws to proceed with voice identification forensic analysis 2) What is the procedure for initiating forensic proceedings. Do I need to provide an application with all the details like App used, Phone model etc. 3) What is the cost of forensic analysis for audio recordings. Does it depend on length of recording (in minutes) 4) Can I submit these audio proofs to a private company and get a certificate that files are not tampered ? If yes how much does it cost ?