Re: I'm (not) sorry
All you are achieving is for Facebook's data to show that these people called you, but didn't get an answer, rather than did.
That's exactly the same thing that would happen if you were, for instance, dead (so long as you never call the people concerned). I would be quite pleased if Facebook decided I was dead as they dead people are uninteresting to advertisers.
So that looks like a result to me.