It’s not necessarily gone to another person, it could be that it’s in limbo because I had a similar issue and couldn’t get it back minutes/days later ect. I ended up speaking to someone and they told me most sites don’t re use names without a big hassle so they just sit there. From what I understand you need to write to them, though the person I’m using as a reference had a trademark so he was going in via that front. I think if you could maybe show you used it before, explain the mistake, you may get lucky. With the trademark claim it was all about how he had used it, built a name under it ect