If they waste my time ignoring my instructions, I return the favour with a lengthy response on every infraction with “the need to follow a structured troubleshooting methodology in order to be able to resolve the root cause at hand, including strict adherence to each individual step in the provided action plan, such that we can progress toward blah blah blah…”

After a few tries they usually get the message that it’ll be faster to just follow the instructions 😄