Credit Card Frozen

My credit card account was frozen without notice, I had to find out at the till trying to buy my groceries! Apparently FNB decides FICA documents are missing a freezes the account. No request for documents on email, sms, call or FNB app. No warning that it will be frozen or has been frozen, just wait for your next spend. App secure chat unresponsive. 9 calls to the call centre, over R150 in airtime, data costs and 2 hours of my time, only to be told by the call centre agent that I should phone again on Monday as she has no idea what documents are missing. Pathetic service. Why should I keep my accounts at FNB?