About the invitation

I've been using the website for like a long time? Anyways

I wanted to get myself an invitation for an account and it was supposed to be today I checked and my name was no longer on the list for some reason

Me: OK maybe I got it? cheaks email Me: I guess no...

So I went and made another request and it was also proved?

So I'm here asking how does this work because I'm confused and I'd like some help