Diff. in TDS Amt. in Certificate & In Online Tax Credit Stat

As iam working in a limited compny, & we have received TDS Certificate for Ass.year 2009-10 from a party that shows the amount actually we received but in NSDL site to view tax credit statement in our PAN NO. for that particualr year the amount is shown by that party is less, so which one is correct whether hard copy of TDS Certificate or only Tax Credit on NSDL site, as their should not be mismatch. so what we can do to call that party for Revised Return to show that much amount  or to leave as it is, please reply