I’m being overly cynical, but then this problem disappoints me. The most common GW complaint is, “Why do I have to fight people who aren’t even trying to compete and be punished for it?”
You can file a support ticket, but you see the response above. GW results are final, and scores aren’t adjusted. If you fight a 0-member guild, you get nothing for it.
It’s possible the guildmaster rage quit and booted everyone from the guild; I’ve seen it happen in braket one and there’s not much the devs can do. Except maybe not let it crash lol.