No bank reversal for system erro

On Friday the 24th of January 2020, I went inside Absa branch to do a transfer from my account to another bank for my tuition fees, when I got home I realized the transaction was debited twice from my account. Went back to the bank on Saturday morning to try and reverse one transaction only to be told Head Office will make the reversal on Monday as they are unable to. Come Monday I am told to I must go to the University to ask them for a refund, because they were told by the University that the bank is a third party and I must communicate with them. I've communicated with the Finance department of the University and was informed that the refund will not be possible as I was owing the University. Why does a bank make a 10 000 error and not be able to reverse it, and why must I be with a bank that's making me lose money. I humbly ask that you assist. Thank You.