Astrid- In effect, I guess they are. It's a credit card I got through the company that does our fringe benefits. Just under half of my wage was paid directly into there every month and couldn't be withdrawn in cash. I'm not sure if it could actually go into debit- though I imagine it could, I never let the balance get down that far. I only worked for a small portion of the year as a permanent employee being paid with fringe, so only had a tiny amount paid onto there (the $542).
I think what has happened is that a balance was left over from the previous FBT year that you then may have used in the one just gone. I could be completely wrong though. Looks like the best thing to do is call the fringe benefits company for clarification as they would be providing the FBT figures for the payment summaries. I have dealt with other FBT scenarios, but not a credit card one so sorry I am not that much help with it.