Not able to remove Snapped LVM Partition

I am actually facing an issue removing a LVM paritition, which is a snapshot of another LVM. The original LVM parititon gets snapped everyday for backup purpose and by the end of Backup Activity, this snapped Partition is removed by a script, which does only unmount and remove the snapped LVM. But now, its not working. Whenever I am trying to unmount the Partition, it shows the Device is busy, so, I found the files which were being used in this Filesystem, so I killed the Processes, and tried again, but still the same issue, I found that, There is one Service from Commvault certification course (Backup) Application using this LVM, so, I stopped the Commvault and made sure, nothing is using this Partition, but still I get this error, that the device is busy. Now, I do, lazy-forceful Unmounting, then again, during lvremove I get this same error, that Device, is busy, but this time I can't find what else is using this Filesystem/LVM. Please help finding out how do I resolve this issue, the issue is on a Production Server, so, We got permission for rebooting once, at that, time this removal worked, but, as we are getting this error everyday, that the new snapshot can't be created as Previous day's Snapshot is still present, so I am out of options to how to remove this snapped LVM with on Online System