I had never heard of a guitar string coming unwound. Snapping, (breaking), sure... constantly.... but 'unwound'?
Being picky about strings.... some years ago I was in Fresno and remembered to stop by the music store for some supplies, so I called Rick, our bass player, to see if he needed anything. He did... some strings... told me to pick them up for him then VERY explicitly explained which strings to get... had me write out the entire packaging label... and THEN... called me at least a half dozen times reminding me because it HAD to be those specific strings and since I was just a stupid drummer I could easily make a mistake.... in fact, when I was paying for them he called and demanded to talk to Dana, (Dana is the owner of the music shop and a good friend of ours), so he could confirm I had the correct strings.