ST billing

Hi Dear All advance rcvd 500000/- and bill should be show 453309+46690.84 st.=500000/- at the time of prepration of final a/c st liabilities show rs 9339/- bcoz of bill was made rs600000/- and file the return on 29.09.10 and 3 qtr has been end. but did not make any adjestment. and not rcvd any amt from debitor . my Q is there is liability 9339/- which was not actuly. what should i do ? thanks in advance .