@DavidR,
I talked to the same Microsoft Tech again today. He took control on my computer and he done the same thing all over again. He brought up a screen and it showed reset, keep files or delete everything. I didn't want to do either one and I told him I didn't. He is supposed to call again on April 26 @5PM but I'm not going to answer. I don't want to go through the hassle ever again.
EDIT
typo
At least you accepted the call to find out what his plan was.
But why you didn't accept one of the 2 options:
1. delete everything.
2. reset, keep files.
Option 1. Really isn't something to go for as it would effectively be a clean install of windows, presumably that would be 1809, but that is something you have to ask him. Obviously you would have to be prepared to reinstall everything and restore your data/image files, etc. from your backup images. You see where I'm going with this you have to have a robust backup and recovery strategy, to recover from issues like this without having to delete everything and start again.
Option 2. Surely would have retained the files and programs that you have installed (especially if you have no backups) and only rolled back to the previous version of Windows. Which may or may not have been 1903 (and possibly not the insiders version) or 1809,
this is what you should have asked him.
Finally when he made the appointment to call back on April 26 @5PM,
you should have asked him what his plan was for that support call. You have to clearly state to the support tech what it is you want, I'm guessing this would be a non destructive rollback to 1809, leaving your installed programs and data files intact. Have/did you clearly communicate that ?
Simply not answering the call isn't going to help you one little bit (not to mention rude, when an appointment was made),
you will be in the same boat as you are now, no doubt frustrated. I don't know if having signed up for the insiders program you would remain on that, at the very least use that call to find out how to leave the insiders program and confirm exactly what it is that you hoping they can achieve in that appointment.