How to send disconnect to pptpd client?

Question

VPN

There is a server with pptpd on centos
there is a client on win
the client connects / disconnects without problems, but sometimes you need to kill the connection from the server side
tried
service pptpd stop
and ifconfig ppp0
on the server side everything is killed, but the client remains hanging in the "connected" state
how to tell him "Walk, Vasya, the shop is closing"?
Thanks in advance