It looks that you can't install mongodb-org-server package if you don't have systemd even though there is section about configuring it post install on mongodb docs. In order to make it work I downloaded package from theirs download center for my distribution and found and analyzed the service script.
ExecStart=/usr/bin/mongod --config /etc/mongod.conf
So in order to run server just ensure that you have folders from your mongod.conf and mongod.conf itself. You probably have those after failed installation but even if you don't you can create folders and take mongod.conf from downloaded archive. By default folders they are /var/lib/mongodb and /var/log/mongodb use this command to create them if they don't exist and location for mongod.conf is /etc/mongod.conf
sudo mkdir -p /var/log/mongodb /var/lib/mongodb
Also you have to ensure that user who is running has permission to access folders. If that is not your current user, then put that user instead of `whoami`
sudo chown `whoami` /var/lib/mongodb /var/log/mongodb/
Now you can run your server manually with
mongod --config /etc/mongod.conf
Here is the whole mongod.server from archive if anyone is interested
[Unit]
Description=MongoDB Database Server
Documentation=https://docs.mongodb.org/manual
After=network-online.target
Wants=network-online.target
[Service]
User=mongodb
Group=mongodb
EnvironmentFile=-/etc/default/mongod
ExecStart=/usr/bin/mongod --config /etc/mongod.conf
PIDFile=/var/run/mongodb/mongod.pid
# file size
LimitFSIZE=infinity
# cpu time
LimitCPU=infinity
# virtual memory size
LimitAS=infinity
# open files
LimitNOFILE=64000
# processes/threads
LimitNPROC=64000
# locked memory
LimitMEMLOCK=infinity
# total threads (user+kernel)
TasksMax=infinity
TasksAccounting=false
# Recommended limits for mongod as specified in
# https://docs.mongodb.com/manual/reference/ulimit/#recommended-ulimit-settings
[Install]
WantedBy=multi-user.target