Start and stop for service

Hi all.
I hope someone will be able to solve this problem.
I’m trying to remake the required functionality for the service from /etc/init.d/ to the systemd.
Part of the script where the start and stop functionality looks like this:

DESC="Veeam Agent for Linux service"
DAEMON_ARGS="--daemonize --pidfile=$PIDFILE"

	start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON --test > /dev/null \
		|| return 1
	start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON -- \
		|| return 2

	start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile $PIDFILE --name $NAME
	[ "$RETVAL" = 2 ] && return 2
	start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec $DAEMON
	[ "$?" = 2 ] && return 2
	# Many daemons don't delete their pidfiles when they exit.
	rm -f $PIDFILE
	return "$RETVAL"

In the snapcraft.yaml I specified this for the service:
command: usr/sbin/veeamservice --daemonize
daemon: forking
plugs: [home, network, daemon-notify]

Snap package during installation starts the service, it works.
But if I try to stop it, then do not start it.
Can anyone tell me how to correctly start and stop for the service?
If I try to use command as
command: usr/sbin/veeamservice --start
it’s not worked

systemctl status snap.veeam.veeamservice.service
● snap.veeam.veeamservice.service - Service for snap application veeam.veeamservice
   Loaded: loaded (/etc/systemd/system/snap.veeam.veeamservice.service; enabled; vendor preset: enabled)
   Active: active (running) since Wed 2018-09-19 20:26:30 CEST; 7s ago
  Process: 31783 ExecStart=/usr/bin/snap run veeam.veeamservice (code=exited, status=0/SUCCESS)
 Main PID: 31798 (veeamservice)
    Tasks: 3 (limit: 4915)
   CGroup: /system.slice/snap.veeam.veeamservice.service
           └─31798 /snap/veeam/x1/usr/sbin/veeamservice --daemonize

сен 19 20:26:29 blin-System-Product-Name systemd[1]: Starting Service for snap application veeam.veeamservice...
сен 19 20:26:30 blin-System-Product-Name veeamservice[31798]: Service started.
сен 19 20:26:30 blin-System-Product-Name veeamservice[31798]: Initializing log file [/var/log/veeam/veeamsvc.log].
сен 19 20:26:30 blin-System-Product-Name systemd[1]: Started Service for snap application veeam.veeamservice.

This is the status immediately after the snap package is installed.
And as I wrote above, starting in this form works, but stopping the service and starting does not work.