Extremely disappointing service from FNB

I am so furious right now given that I am a STUDENT and have a STUDENT ACCOUNT with FNB. I login to my FNB banking account this morning, only to find that I was charged for a foreign transaction which I never made. This transaction shows "Declined Foreign T 457". FNB , WHAT IS THIS FOR AND WHAT DOES IT MEAN ? Why was I charged for a transaction I had not made? I always receive a notification giving me an OTP upon transactions should i make one but this is absolutely absurd. I refuse to incur bank charges for transactions i have not made ! I also have no Apple subscriptions so please sort this out ASAP and REMOVE those charges from my bank account. As a student, especially during a difficult time like this, I should not be expected to pay for charges i had no dealings with.