You have not received the money which is due to you.
Therefore the person still owes it to you.
It is up to him to sort it out. Of course, you try to help him. But it's possible that he entered a wrong account number, but that is his fault.
Why did he go to an AIB ?
He should have gone to a ptsb to transfer it to your account.
Or to EBS to lodge it to your account.
Why did he complicate it by going to an AIB? Did he give them cash? Did he get a receipt?
Brendan