Discovery Bank

I have been a customer for a few months. I’ve been doing account payments by transferring money from my transaction account straight to my credit card (both with Discovery bank). According to my statements, I have zero amount/payments overdue. Today, I get a message telling me my account is locked for non payment. I called Discovery Bank call centre and was told that my account cannot be unlocked and the only way to fix this is for me to downgrade my accounts, which can take 11 days, then only I can make a payment. This is not acceptable.