If I was dropped from an NCOES but never received a DA 1059 from the course, what can I do to fix this?

If you did not attend ,though scheduled but had a course number and date, the accountability notation of non-graduate applies once you were dropped from the course. The main purpose of the DA 1059 is to illustrate the accomplishments, abilities, and overall potential of the Soldiers "ATTENDING Army Learning Facilities or participating in military training courses.
"The DA 1059 Form consists of fifteen sections and is completed by the student and the school/course representative."
You did not attend, by your own statement herein RP, thus the school would be in violation of the detailed guidelines found in Army Regulation 623-3 of the Evaluation Reporting System.
However if your Chain of Command approves a waiver, you can request for another school date.

If you were unable to attend because you were a no-show, then that is the correct annotation. You'll have to get your CG to sign off on getting rescheduled. If you processed a course cancelation, then you can contact the school house, show them the approved 4187 and they change the ATRRS annotation to canceled. If you weren't able to make it and no cancelation was ever submitted and approved, then it is considered a no-show. It's a 4187 to your first Commanding General to request another SLC class date.

So your S1 / Training NCO needs to go into DTS and update your training record. It will more than likely have to go up higher depending on if you are company or Battalion. But it’s your training record that needs to be updated.