So I am a software engineer and currently have lots of clients that I create and maintain websites in WordPress.
One of my clients, who I have a maintenance contract with(fixed $ / month) wants to be involved in certain aspects of the website, such as customizations and time to time changing functionality on their own.
When they attempt to do this, most of the time, they fail and either crash the website or just don't get it working.
At this point, they inform me, that they wanted to make A work and broke the website and they want me to fix it. After I spent time figuring out their error and fixing it, they always want step by step documentation on what I did to fix it and what they need to do in future to make this work.
I have told them a couple of times, to not try to make/change things on their own, but they claim they want to know how to do simple stuff on their own.
Now, they are paying me per month, fixed rate, and it gives them unlimited items to request. Thus they won't be paying extra if they ask me to do it instead of them.
What I am coming to conclusion is, that they are slowly collecting documentation of how to do most items and will eventually either downgrade their maintenance plan with me or completely cut me off since they know how to do to everything they need.
How should I go about this?
Should I tell them that I am no longer supplying documentation for my work, or should I supply it if they want?
What is the correct approach for this situation?