Unlinked contacts and now texts are under wrong contact

[Windows Central Question]

I have a Lumia 928 8.1 phone. I don't ever want contacts linked. The last update automatically linked many contacts. I've been un-linking them as I find them. Something happened this week and a close contact with a long history of texts (that I want to keep), got linked to a contact with no phone #. I un-linked them. Now that long history of texts is showing up under the guy with no phone number. And it says "Read-only message". I started to delete the guy with no phone number, but it said it would delete him from phone. I worried that meant it would delete the text chain, so I canceled the delete. How do I get that chain of texts back to the right guy?