Automator service not showing in services menu
Depending on how your script is configured, by default, any Service requires to have an item selected / highlighted (in your case, an email) as they are context sensitive.
You can disable this behaviour by changing the drop down field "Service receives" and selecting "no input". This obviously only applies if your script fetches input itself or doesn't need it.  

  

Unfortunately there do seem to be weird issues when services have spaces and/or numbers in their name.
As stated by @gerlos, renaming them should solve the problem, but a reboot might be required (Which was the case for me).

As an extra;
If you're now finding that you don't like the name of the new service, you can change it!
Just right click the .workflow file and select 'show package contents'.
Inside you'll find a configurable info.plist file.
Open it up with your favourite text or plist editor (Or just plain old TextEdit) and look for the xml key 'NSMenuItem', it should contain a key entry 'default' associated with a string, the string in question is the service's display name. 

More information on everything that's configurable (e.g. a service description) can be found in the apple documentation here: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/SysServices/Articles/properties.html  

Tested on OS X High Sierra