The scammer claims they sent you money or airtime by mistake and begs you to return it. Either nothing was ever sent, the 'payment' SMS is forged, or the original transfer is later reversed, leaving you out of pocket for the 'refund' you sent.
You receive a forged confirmation SMS, or a real small transfer made with a stolen account.
An emotional call follows: 'that was my last money, please send it back'.
You refund from your own balance; the original credit never existed or is reversed by the bank.
Airtime variants ask you to 'return' a top-up or package sent 'by mistake'.
A 'payment received' SMS that doesn't match your real balance.
Urgent, emotional pressure to return money quickly.
Refund requests directed to a different account than the one that paid you.
Check your actual balance or statement, not the SMS, before believing any payment arrived.
Tell the sender to reverse the transaction through their own institution; genuine mistakes are corrected bank-side.
Never 'refund' from your own money, and never to a different account.