This can happen when at some point the call details received from the PABX was future dated. TNG will only show the last 50 calls for today and yesterday. If you have future dated calls, you will only see it on the Call List on the day of the future date of the calls. It could be some time after the PABX had a date problem and can stretch over a period.
To get rid of the calls in the future(and the ones that will only be seen the next day, etc.) is to blank the TNG database and to only import the rawdata collected after the PABX date was sorted out. If you do not know when the problem occurred, you cannot re-import the rawdata as we will then import the incorrect dates again, having the same problem again.
See forum post:
How do I blank the TNG call details?