FNB cancelled my card without my knowledge

Today at 07h54 I received an SMS informing me that my card had been cancelled. During operating hours I called in and was informed that the card was cancelled by an investigator in their ***** department in error. They explained that the person who cancelled my card made a mistake. I enquired as to what was the reason for going into my account in the first place and the person who was assisting me at that time didn't have an answer. I asked if there was any suspected ***** on the account and again the person on the other side of the call had no answer. I am shocked to find out that someone who is employed by FNB randomly selected my account and just decided to cancel the card. I am currently unemployed and expecting a payment from UIF but this incident has led me to decide to change the bank where my payments will be deposited.