Unknown deductions

On Saturday the 16 July 2022.I got a notification on my phone of amount of 599.85 that has been debited and I have not buy anything with my card. So today I went to the branch and explain my case. They said it's an online shopping but for online the maximum amount that I set can go through is R50. And I didn't receive any notification that someone is trying to do transaction of 599.85 it just went through. So my question to them is how can an online amount of R599. 85 went through but my maximum amount for online is R50. And asked if it's possible if they can reverse that amount to whatever company that deducted the amount because it's not showing on the debit orders you can only see on the bank statement. They made a call after that they said I must wait for an sms if there's no way that I get a refund I'll be responsible to pay R80 charge back fee whether I get my money or not I must pay. As if it's my fault for all of this. So I struggle to dispute on my app. Please help