This app was mentioned in 4 comments, with an average of 3.00 upvotes
I use this one and it works really well. I've never had a problem hearing the other party I am talking to.
Tip from me: make a couple of test calls using speakerphone, ear buds with mic, and regular call, and flipping between three to make sure all of those record the other person. I've had a few apps that didn't record with earbuds for example. One app I had did great with mic but not on a regular call (no speakerphone, no earbud with mic' just phone to ear).
Here how I've been fighting these. Assuming your on the do not call list.
Record the call ( i use https://play.google.com/store/apps/details?id=il.co.smedia.callrecorder.yoni)
Try to get them to provide you with as much info as possible and as clearly as possible. "I'm sorry can you please repeat that but louder?", " I didnt catch your name, can you repeat that?", " where did you say you where calling from?"
Send recording to various agencies
I've used this one about a week ago. Worked good, also remembered numbers. Maybe something changed in the meantime, but give it a try.
I too use Call Recorder, but it's a different free app with the same name. Works fine if you keep it open in the background.