Nightmare with FNB!!

I have had a nightmare with FNB regarding a personal loan. I have been going back and fourth with FIRST NATIONAL BANK CAPE TOWN. I have been pre approved for a R90 000 loan via my FNB cellphone app, I went into it and reviewed the loan, I was then sent an email stating that I would need to send relevant documents before the loan is paid into my account. I did NOT send back ANY documents nor was I even contacted to have this authorized. On Wednesday, a R50000 was paid into my account, immediately I went to Zevenwacht mall and explained my frustration. I then reversed the R50000 back into the loan account and now I am apparently liable for a R1200 initiation fee, which the lady at Zevenwacht mall branch told me not to worry about as I will not be liable for the payment. I was also advised that this will not affect my credit record, well it did. I've been calling the bank back and fourth begging and pleading them to remove this from my name RIGHT AWAY but they are insisting that I should wait 40 days. I was even more frustrated that NO SECURITY QUESTIONS OR AUTHORIZATION was asked by me when this money was paid to my account, but when calling into the bank, a bunch of security questions are asked. WHERE IS THE LOGIC in this??? I want this off from my name RIGHT AWAY. I've been waiting since Wednesday for a letter stating that I am NOT LIABLE FOR THIS BUT I AM STILL BEING IGNORED AND ALL I WANT IS A LETTER AND I AM BEING ASKED TO WAIT 7 DAYS FOR THIS!! I also posed the question that what if my phone or laptop was ****** and someone else accepts this loan on my behalf?? The agent then said "then that's on u", does this mean that FNB is not a safe banking platform? Please just sort this out ASAP!!!