So the legal folks are finally tracking you down. Well in any case using your iPhone unfortunately it's really not possible to record your calls. If you want to record a call when iPhone you have to use some other tool and the simplest is to use the Google voice app. It includes a button that allows you to record a call.
If you're on android phone it's actually easier. There are apps that allow you to record a call including one that I read about, but haven't tried, called "record my call".
Of course there are legal implications of recording a phone call. You need to alert the person on the other end of the call that you are recording it. But any case on the iPhone without using a different calling facility like Google voice you won't be able to record the current call. Think about however it's not really legal to record a call with another person without letting that person know.