Once the Ovpn is assigned to one user unable to disable the Ovpn

[Mav215]

Once an Ovpn is assigned to a user, that user cannot disable the Ovpn. When I try to do this, I am attempting to delete the file from the directory, but I am unable to restrict user access; if anyone knows how to do this, please tell me the command to disconnect a client from the OpenVPN server or give me the code that works.