The Debit card i blocked is still making transaction on my account

I am going through a very tough time and by far the worse experience because of FNB. i lost my card just a few weeks back and immediately when i found out that day that my card was missing, went to my online banking app and reported that my card was ****** and i blocked the card via my online banking app. but after three to five day, i started seeing some transactions on my account and the transactions were made using the same card i had blocked and then my account went into a negative balance of R -2,000 . Then I went to FNB and opened a case to the ***** department and the case number is ***. But still my account continued to make transactions to that card and of recent the balance went u to R -7,990 . They said they are working on it, but transactions are still happening on my account and the money is mounting to big amounts every time.