Recycling Account Numbers FAIL

How to you recycle closed account numbers so soon after said account has been closed??? Aren't there enough unique numbers, I mean how many clients can you have? This is obviously going to lead to lots of people paying EFTs into accounts because the person's details are not up to date!

My mother closed her Standard Bank Account a while back. I have not updated her banking details on my side and payed an EFT to her. After realizing that the money is not reflecting in her account (Because it is now with a different bank) I started to investigate and found that the details are not up to date. You would think that the transaction would just bounce, but no, it was successful!? Because they somehow recycled the account number a couple of months down the line? How ' to you think that is logically sound?