I was recently in a situation where I was responding to a customer inquiry about the availability of a certain action in our API that is present in our desktop application.
Their question was not very clear so I had to speculate about what they were really looking for and I came up with two things I thought could be what they wanted.
I emailed them back a fairly long walk through of what each action does and what is available for each in the API, expecting them to respond with which one they want to use. The customer instead emailed back more questions about the two APIs I just explained, the answers to which were in my previous email.
My question is how can handle a customer who doesn't read the information you provide them and then asks questions that are answered by said information?
I don't want to re-type everything or copy-paste it, but I also think it comes off as rude to refer your customer to the email they just replied to. I considered starting off my email something like
Hi so and so,
As I stated in the previous email, the API blah blah blah...
but to me that still sounds rude/condescending and I still have to retype or copy everything from my previous email.
I have looked at this question which is similar, but that deals with internal emails whereas this is about interactions with a customer which tend to be more formal.