FNB Bad Service

I have recently joined FNB and thus far I am not impressed. Firstly I had to wait for more than a month for my card to be delivered to me initially as the assistant forgot to process it. I finally got the card set up the App & online banking and when I tried to do payments via the App I get a message about my credit limits that need to be increased. I went online to resolve the issue and whilst trying to confirm my online banking I noticed that the mobile number linked to my account is an old mobile number which has been cancelled for more than 10 years. I contacted FNB and the assistant said I should go to an ATM and make changes at the ATM. I get to an ATM, follow the instructions only to find that the listed contact numer on my profile is my current mobile number. NOW WHAT? I need this matter resolved urgently as I need to make payments. I am highly disappointed in FNB's lack of support and am considering closing the account before having to put up with any more setbacks.