***** on my debit card

I received a notification stating suspicious activity on my account or card. I then checked, and close to 30k was taken off my business debit card. I canceled my card immidiately and opened a case of ***** with fnb. I now receive an email from fnb stating that it is not their responsibility and I will not receive my refund. Absolutely ridiculous. I have been banking with fnb for over 30 years. This needs to be sorted asap and I need to be refunded. I also did not receive any otps or a notification to approve the transactions on the fnb app. The money was just taken out of my card.