Just came accross this on their web page. They're doing an upgrade to their credit card system.. Long story short, don't rely on your credit card working on Sunday 13th, ie, have a plan b.
How will this affect me?
From Friday night, 11 April until Sunday morning, 13 April the Suncorp Bank credit card services affected will include:
Suncorp Bank credit card online and mobile banking
Limited ATM functionality for Suncorp Bank credit cards
Online credit card applications will be unavailable
Early Sunday morning 13th April:
A small number of transactions may not go through
Cash withdrawals using Suncorp Bank credit cards will not be available
What do I need to do?
If you’re planning on using your credit card during the early morning on Sunday 13th April, please make sure you have some other options you can use just in case your transaction doesn’t go through.