Bad service

I am livid my brother transferred money to my account and he is capitec that was 25th october 2019 an error showed and then he tried again and then it double eft the money so it was 4400 altogether.. i contacted my bank which is fnb and no money was sent, my brother went to capitec numerous times and he foned also they wanna investigate.. and it shows on his statement that R4400 was deducted they say its not their problem and that is our rent money!!! We wan t our money !!! I am not going to leave it like this very bad service capitec why can other banks reverse and u cant?