Most likely, you are just seeing the accurate reporting for the billing cycle of your phone.
When you uninstall an app, the report will lose the name and give it a number so that the monthly report is accurate.
When the new month starts, the odd app/number is removed from the report since it is no longer using data.
If this is not what you are seeing:
Which phone?
Which version of android?
Which carrier?
Which apps did you remove?
Can you show us screen shots so that we can see what you are seeing?