I appreciate the context that you have shared with us as that is very helpful. I saw your post and wanted to help out where I can in this situation.
If your products have been rejected by Instagram, we may be able to see the reason to why this has occurred. You can navigate to the Facebook Sales Channel, you an select on the Not approved products to view the reason why they have not been approved. I took a screenshot from my test store to show you what the section looks like: