No more FNB, no more!!

I Bank with FNB and I have overdraft on my account. I do not want to have the overdraft anymore and just want to cancel it. I have tried canceling online but I couldn't and I only managed to decrease it to a R1000, I then contacted FNB on their secured chat, but they told me I need to call and I did then they made me wait forever before the call was answered. I also told the lady I was speaking to that I have reversed a debit order but the funds were still not in my account, she refused to let me speak to her line manager, told me that she has "escalated the matter", I asked her to cc me on the email, she did not. I am so Unhappy with fnb. I just wanna cancel my accounts with them.