disheartening customer experience!!

I’ve been with FNB for many years. I was offered the FNB credit card over 2 years ago. I took the card and have been paying only service fee since I settle my account in full each month until last month when I was charged an interest fee of R143.88.i went to the branch and was told that credit card enquirers are done telephonically. I thereafter called in to enquire about the interest, the first consultant by the name of Kgothatso was a very inpatient and had bad attitude when assisting me, the telephone line cut, I’m not sure if she terminated the call or it was a network issue. I called the 2nd time and had to go through the verification process again, the consultant who was assisting me was Wandile, what a great customer experience. He mentioned to me that he will escalate my query further as he is not sure why the system started charging interest only last month. I got an sms in February that they have created an auto payment to be aligned to my payment day but surprisingly when they offered me the credit card they called me. I only realized about the payment options when Wandile explained them to me. The feedback I got from the escalated query included T’s&C’s to view by email, no call from Refilwe Rakgoathe .I’m in a process of closing this accoun***** not even about the R143.88 interest charged but the principle.The time i spend on the phone was more or less the interest i was charged. What a disheartening customer experience!!