I once left a small design agency due to toxic management. They extended my probation which was a massive red flag for me, so I immediately went job hunting. I managed to get a new offer, more money with better stability. I hand in my notice and they're practically begging me to stay. After leaving, I left an honest Glassdoor review about my experiences there, how the work was great but management lie to clients, micromanage your time and don't prioritise the well-being of their staff.
Cut to a year later into the new job and I get an even better opportunity elsewhere. They require 2 years worth of references… I request this from the toxic job and get an email saying “tell you what, let's do a deal, if you remove the Glassdoor review, we'll provide a reference”. These guys were holding my reference hostage, and not only that they emailed this to me, so I had evidence. I was panicking but decided to share the situation with the new place. Thankfully they saw this as a bad reflection on the toxic company and after I shared evidence, they decided out was fine to veto their reference and I got the job.
I replied to the toxic company saying “I've shared all this with the company and they've decided they don't need your reference. P.S. the review stays”. All I got was a reply saying “Message received”.
Since then I've noticed they've had a suspicious increase in positive reviews, no doubt faked by themselves, to try and mitigate the damage.
TLDR; I left a toxic company and submitted a negative Glassdoor review. Got a new job and needed a reference from them, they said they'd provide one if I deleted the review. Informed new company who said they would ignore it because they're being shady.