Wrong Account No, need to reverse that money

I deposited money into a capitec account by mistake. I do not know who the owner of this account is. All im asking Capitec to do is to alert their client that money was incorrectly deposited into their account. FNB will do what they need to do on their side but im getting no joy from Capitec. Do I now have to suffer for making a mistake? I am a Capitec account holder and was in the process of converting to them but Im highly disappointed as they clearly do not care about their clients.