Maybe a combination of string as close as you can match and wood glue for a temporary fix.

But after nearly 2 decades, UV rays, wear & tear have done a number on all of the strings so I would be looking for & planning replacements.

The problem is this blind can no longer be raised or lowered. The broken threads make it completely non-functional.

if you look on the back of the shade you should see rings that hold the pull string (similar to pic below). the rings probably detached when the threads binding the slats broke. How are your sewing skills?

I have seen (in my major metropolitan community) recommendations on Nextdoor for someone who repairs blinds. I think those people are out there. Have you asked on your Nextdoor? (Or, I assume there's some version of local facebook, but I'm not a facebook user, so idk).

You could also contact the place you purchased them and ask. Perhaps the manufacturer has a repair-service.

As a side note, our whole house has blinds we bought through Home Depot, I believe they are Levelor. When I went and asked them how to order replacement slats for a few that were broken, I was informed there was a 10 year warranty, which (for once) still had a few months left. We ended up getting a bunch of replacement slats and new blind, all under warranty, at no cost.

I actually know of at least one place already who does repairs. My concern/question is whether this is even repairable or maybe not affordably repairable. However, NextDoor is a good suggestion. I have an account and I can post my pics there see if I get any feedback/suggestions.

@elunia I have total of 5 rings on rear of shade/blind. Only one ring is loose due to broken thread. I will attach a new pic to show you.

Hmm…what actually happens when you try to pull up the blind? only one side goes up? neither? the blind goes up partially, but doesn’t stack? could it be the pulley mechanism?

@elunia Only one cord will make the blind pull up on one side, but as soon as I release the cord, it falls back down. And just to clarify - the pic above showing my hand with the ring next to broken string is completely separate area of broken string on opposite side of shade than my original pic with the broken string circled in red which is on other side of shade. But both areas of damage are on rear of blind.