$ sudo apt-get remove l2tpns 

Uninstall l2tpns including dependent package

If you would like to remove l2tpns and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove l2tpns 

Use Purging l2tpns

If you use with purge options to l2tpns package all the configuration and dependent packages will be removed.

$ sudo apt-get purge l2tpns 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove l2tpns 

See Also,