Nedbank approves transaction R12,000 over limit

So last night I called Nedbank regarding an unauthorized transaction.

As explained I approved the first transaction of $39 but the second transaction of $2,500 was unauthorized and should have declined purely on a limit basis as it is 33% above what I have available. Now apparently because I approved the first I am responsible for dealing with the merchant who at this point appears to be ********** as I am not getting response.

First consultant really tried her utmost in helping and spoke to authorization who explained it’s my problem to deal with merchant. ***** department also assisted by sending the form to be completed.

My issue remains as to how a transaction way above my limit got approved in the first placed when Nedbank in the past have declined when I’ve been R20 over the limit. What security do I have that I am protected by Nedbank?

As it public holiday I still have no peace of mind other than the form I need to complete.

From a Credit Act view, who is responsible for the amount exceeding my allowed limit on the card? Nobody at Nedbank seems to be able to answer.