Problem with Filters

Hi,

I brought you an excel spreadsheet with the problem. I need to see if the Invoice number is repeated, so we use Filter to see how many times it was entered. Somehow there are certain invoices # that are in the spreadsheet but when you look for them at the displayed list from the filter, they are not there. I though it was from certain line but I was wrong. For example if you search the invoice # 317403, it is at the column F row 1131, but if you display the Filter, you won't see it.