Frustrated and stressed Capitec client

My account with capitec is frozen, I called the customer care line and they told me there's an ******* amount of R800 that happened on the 27 October 2020. Then they decided to freeze my account on the 9 November 2020. I explained to them that, that transaction I know nothing about it as my sim card was ****** the same day the transaction happened. My sim card was ****** by someone who pretended to be an MTN employee and offered to give me some MTN promotions as I'm their client. I reported the case the same day of the incident and even changed my Pin codes because my sim card had all my banking details.

Now I'm being punished by Capitec for that R800 they froze my account, I don't have the money to go to work, I'm frustrated I can't access my money. I've been a loyal client to them and Capitec is the only account I have even my salary is paid via that account. I don't know what to do any more, because I wasn't contacted about this whole issue. I just found out while I was trying to pay with my card at the shop, and then tried to withdraw it decline and said valid transaction.