Voice recording is acceptable as a evidence in income tax ?

Dear Seniors,

I need your help regarding my case in income tax, one of my friend used my account for heavy transaction in share market after some years I have received notice from income tax department that I have to pay Rs.11 lakh tax to the department, I have given in written to the AO that these transaction done by my friend and I have given many evidence also to them but they are not accepting it.But now I have got mobile number of my friend and his father I told them about my problem with income tax department which is only created them, they are accepting all the things that they used my account but they are not ready to give in written but I have recorded there voice in my mobile and now I have call details from Airtel also,
that  the same time they talked with me and the conversation is also recorded.According to the law is this voice evidence is helpful for me ? or just waste of time .

Please reply me and help me to come out from this problem

Thanks.
Mirza Seraj Baig