What's up with Standard Bank?

What's up with Standard Bank these days? There's an error on my revolving credit account, balance suddenly zero...and I suddenly owe them a huge amount!, a rediculous amount! Send them an email and they eventually call me back telling me there's and error on my account and IT is working on it, but they don't know what the problem is. A week later no resolution! Sad because I have banked with Standard Bank for over 25 years, really sad! Could someone at Standard Bank please inform me where the money went that was in credit in my Revolving credit account?