Unsuccessful Reversal Request

I am utterly dissatisfied with FNB and I'm even considering another bank...

About two weeks ago I incorrectly transferred funds (R12,000.00) to an FNB account and them requested a reversal and according to FNB outcome the recipient "did not give permission to the bank (FNB) to reverse the money" and without that there is nothing they can do. FNB customer service said "the bank may, in good faith, provide you with further details to assist you in approaching the recipient directly to recover your funds."

So, they sent the contact number of the person, which I tried to call but the number ha been going to voicemail for the last 2 days (never managed to talk to this person, I suspect she even changed numbers).

Okay, FNB can't reverse the money without the recipient's permission, but can't FNB freeze the person's bank account in order for them to re-think and eventually pay back the money that does not belong to them?

We are both FNB customers, if she won't pay back the money knowing it does not belong to her, then why can't you (FNB) freeze their account? How is that fair?

FNB will just let one of their customers lose money "in favour" of another customer.