Charged for cash back that declined

On the 09 of June I was doing a cash back my card declined although I had money on the account, I went to a spark atm Inside the store to withdraw I withdraw money. However on my bank account it reflected that the store had processed the money 280 rand that declined on the 9th on the 11th, I went to the pmb branch store in pmb branch check sa***, to complain about this they told me I need to submit my bank statement of which contains my entire info which am not comfortable with so I offered to give my last 3 digits of my account and info of the time everything else but was refused I need answers