Appalling service from FNB

I found out that I have an overdraft account yesterday the 28th April 2020 which I did not apply for or request. When I tried to cancel it, I got an error that I am only allowed to change the amount to R1. I changed the balance and this morning woke up to a notification that my debit order has bounced back. After logging into my account I saw that my balance was a negative amount so I contacted FNB, after my call cutting several times I finally got a hold of a consultant who advised me that the overdraft account was opened in 2018 which I was not aware of. When I asked for a document in which I signed up for this or proof that I app****, the lady could not provide one as she said it was approved online and no one from FNB contacted me. The consultant then continued to say that it was a charge on my statement label “MOD” as though I am supposed to know what that was as there are so many different acronyms on the bank statements. I was then transferred to the overdraft department to try and get the amount back however I was told that they cannot do anything about it and that the amount can only be changed after 30 days. I am now sitting with unpaid debit orders and a negative balance on my account during the lock down and no help in resolving this from FNB whatsoever. I have been an FNB customer for the last 5 years with no issues and no hassles from the bank however after this whole episode, I am strongly considering switching banks