Not allowed to edit contact details and owing *** on account

I have a Kulula Credit card which had expired in November 2017. Unfortunately, my statements for the account are neither mailed to me or emailed to me, and since the card has expired I don't have online access to my account. I'd received a mail from FNB, however, which states that I owe R ********** 84500 on my account. I'd phoned FNB/kulula to change my contact details, as my phone number had changed months ago, but was told that since my payment is late I am not allowed to change any details. I am therefore not allowed to change my contact details for Kulula/FNB to contact me about my account.