If there is a negative balance in your unit’s statement, it indicates that there are dues against your flat that are to be cleared by you.
If there is a positive balance in your unit’s statement, it indicates that you have paid in advance.
Please note: If you have paid any amount as a deposit to the society, your account balance might be zero or positive, but still, you might have dues pending to be paid. To know this, please go to Home->Make Payment – if there are charges listed with the pending amount to be paid as a non-zero value, you have dues to be paid (irrespective of your statement’s balance).