First make sure you are sorted in Date order with the newest date at the bottom. If you are not then click the DATE Column heading to sort.
Sounds like you might have a credit balance. Is the balance in red or black? Look back through your transactions and maybe you'll spot one that was entered backward. Or a payment in the charge column or a charge in the payment column. Look around back where this first started happening. Or maybe you are missing some charges?
If the balance is in Black, it means you have a credit on the card. Like if you overpaid the bill or got a refund for something you returned. When you enter a charge it will reduce (decrease) the credit you have available on it. And a payment will increase the balance.