I wrote this request to a supplier:
Please don't send the order before all records from the series have been out
I now want to write:
After I ordered both records, I wrote you not to send the order before all records from the series have been available
Can I use present perfect with no need to backshift, as I know all records from the series (at the time of writing this message) have not been out yet?
The present perfect describes past events that have some relationship to the present time. That's why you can't say
I have been sick two weeks ago.
Two weeks ago is a fixed point in past time, and presumably you're not sick now. So you have to say
I was sick two weeks ago.
You may say
I have been sick for the past two weeks.
because the past two weeks counts fourteen days back from now.
Directly quoting one possible version of your letter:
"You are not to send the order before all records from the series are available."
The availability is some fixed point in time. After the release of the records that point will be fixed in the past and won't have any effect on the present. Thus when you backshift for indirect discourse you'd use the simple past tense:
I told you that
you were not to send the order before all records from the series were available.
Notice that the merchant could send the order any time after the release of the entire series, right up to the present moment. Thus the following is possible:
I told you that
you were not to have sent the order before all the records from the series were available.
