FNB Payment Reversal

I have wrongly deposited the money to the amount of R 42,621.21 to the Bosch R55 Service Centre Centurion to the previous partner as they have removed the partner, when we call the previous partner he managed to send back the R 29,000.00 that was left from his account as he was owing the bank charges, when I call the bank they said they can't reverse the bank charges amount as the client was owing the bank. Which I don't understand on why should the bank take my money as the bank charges while the money was wrongly deposited. I want to be paid back my money of R 12,621.21 from the R 41,621.21 paid as the owner of the account manage to send back the R 29,000.00