How to remove systemd services

My recipe for service obliteration (be careful with the rm statements!)

systemctl stop [servicename]
systemctl disable [servicename]
rm /etc/systemd/system/[servicename]
rm /etc/systemd/system/[servicename] # and symlinks that might be related
rm /usr/lib/systemd/system/[servicename] 
rm /usr/lib/systemd/system/[servicename] # and symlinks that might be related
systemctl daemon-reload
systemctl reset-failed

It is possible that the systemd service 'wraps' the old style scripts in /etc/init.d, so you may want to clean that up too, but that is not where systemd services live.

You are probably looking for reset-failed:

$ sudo systemctl reset-failed
$

From the systemd man page:

reset-failed [PATTERN...]

Reset the "failed" state of the specified units, or if no unit name is passed, reset the state of all units. When a unit fails in some way (i.e. process exiting with non-zero error code, terminating abnormally or timing out), it will automatically enter the "failed" state and its exit code and status is recorded for introspection by the administrator until the service is restarted or reset with this command.

Sounds like you uninstalled it, but didn't remove the systemd hook:

# systemctl disable [servicename]