Question is how do you prove it? And what can you do about it? A few years back a recruiter was gushing at my resume and said the hiring manager wants to talk

Question is how do you prove it? And what can you do about it? A few years back a recruiter was gushing at my resume and said the hiring manager wants to talk to you but wants to know a particular gap in my resume when I left prior employer X. I told the recruiter that I was not happy that X made it very hard for me to take my FMLA leave when my kid was born. The recruiter hung up shortly and a couple of days later I got the generic rejection letter. I responded by stating that this was discrimination & illegal but I don't have any material evidence and the recruiter simply rejected my claim. So I thought I would post my experience on glassdoor. Couple of days later, I see that my review about the company had been removed from Glassdoor. Glassdoor definitely know which side of one's bread is buttered.