Immediate payment problems

I mistakenly made a payment of R3 800.00 to a wrong account * acc no. was missing a single digit*, and I contacted capitec immediately. they said it can not be reversed because it was an immediate payment, and nobody could explain to me why is that so. That is just a option without any explanation or warning that any payments done with this option are irreversible. Ironically the other bank is willing to assist me but capitec My own bank isn't willing to help. Capitec should be doing the reversal not the other bank...