FNB changes you card pin without them or you knowing why or how

FNB - Wow what can I say.... This is now the second time things happen to my account that no one can explain to the just never phone back! First thing happend a bout 2 year ago.... My wife's card got swallowed by a FNB teller(nice), so first thing is firs we cancel the card on the COOL FNB app. Haha joke was on me the next day I tried to use MY CARD.... apparently FNB saw it fit to also cancel my card that had nothing to do with my wife's card or account. Phoned FNB loged a call to find out how on earth this was possible... To this day no response. Then about 9 months ago... I bought breakfast the one morning with my card all went well 5 hours later I tried to pay for some stuff at the post office but my pin would not work? The same pin I used the morning! Went on to my FNB app to view my pin... got the shock of my live when I saw a pin I have never in my live used or saw before! Called FNB, no one could tell my why, where or how my pin was changed all they would confirm is my pin was changed!! I was told there would be a investigation done to find out what happend ( I am still waiting to find out)! Now 2 weeks ago my wife again got a new card as the old one expired... first thing when wrong when the card was delivered 200km away from us and when we phoned to find out where the card is we were asked is it was in any way possible if we could go and pick up the card, even after we told the person it was 200km way!! But ok after I lost my temper it was agreed the card would be sent to the correct address. Now 4 days ago I again tried to pay for goods at the store my pin once again changed without my consent! And again I was told FNB needs to log a call and I would have a representative phone me in 24hours.... what a JOKE! How can a bank have such low security that my pin can change at any time without me or the bank know who, how, where, when or why it changed!!! I do not recommend FNB at all I am now in the process of changing banks to someone who cares about my money as I do!