*****-Repeat

I have had online ***** twice in the space of a year and had to have my card cancelled/replaced as the protocol is to block it, what i cannot understand is that I was in possession of my cards both times and when i do online payments i have to get an OTP and open my banking app to approve the transaction so how is the ***** happening if these prompts are being bypassed somehow. Separately, this time, my account had a zero balance, even my overdraft was depleted and yet 3 transactions went off and put me into a negative, should it not be declined as there is no funds in the account?? I am moving to Discovery Bank as this is a huge inconvenience and FNB must have people inside selling out information or *****ing from their clients.