Unauthorised transactions allowed by FNB

I had R22 rands in my account about a week ago, suddenly a card transaction of R500 goes through @Club Africa in Benoni while I'm working in JHB CBD putting my account on a negative balance, once I saw that I contacted FNB asking them how did a transaction of that amount go through when I don't even have that amount in the account or over draft active and yet the bank let it go through, I was told this was a suspected internal ***** and will be investigated, they froze my account and added an additional R250 for unpaid charges, now my account is on a minus R750 that I was told I'm responsible for, how the hell do I get to take the blame for a flipin ***** created by the bank, I got paid my salary on the same account they took the R750 and yet my account was still frozen and I couldn't do any transactions,

This bank is so bad for the small people, when you call the ***** department they keep saying it's being investigated for more than a week now, so I paid for an unknown transaction that the bank allowed when I didn't have money in the card I want my money back, and this sorted I'm so 😡😡.

I went to Dobsonville branch where they refused to give me a new card after I was told to go get a new one and cut the one I have by the agent I spoke with on the call.

I'll never go back, they ruined my experience with them for all time.