I am being plagued by a call back scam, where I get calls from numbers beginning +224 (Guinea), +252 (Somalia) and a few other countries. The call rings once and disconnects, and I suppose I am expected to call them at exorbitant call rates, from which they get a cut (just like calling domestic premium numbers).
This question tells me how to do it using Android settings, but I can't find the setting on my phone. I asked friends to check, in case I had overlooked it, but they can't find it either.
Is there a free Android app to do so? (I'm looking at you @Izzzy ;-)