Please do not put the conversations or mp3 out on the net. You may be hit with privacy lawsuit. Unless off course the pir agreed before hand that you would be recording the phone conversation.
The maximum you should do is to make his name/address available on the net so other people won’t get into his chungal.
Still you need to be careful if you are in USA. He can come back to you and sue you for defaming.
frauds will remain with us until the day of qiama. you cannot protect the whole world. Just save your family and move on.