Why can I receive a refund message after the money has been transferred from online banking?

Please check first. He did remit money to you. Online banking will arrive on a normal day. If there is something wrong with the account number, it should be returned to the remittance account in about 5 working days.

You can only prove that he has remitted the money when you receive the text message, and there is no guarantee that the remittance will arrive. Not if the account number is wrong.