How can I delete my sites/guilds?
That was a quick turnaround .. weren't you just trying to get it back only a few days ago?!
https://guildlaunch.uservoice.com/knowledgebase/articles/30915-how-do-i-delete-my-site
I can't imagine that most prospective members would immediately go check out your roster page and, if it wasn't up to date, decide not to apply. If you're concerned about it, don't put the roster on the navigation, or place it on navigation that is only showing to guild members.
I'm not sure the roster actually updates itself automatically .. it should, but I've had issues in the past with it, so you can update it manually. If that doesn't work, I'd flag it up to Customer Service by clicking the little chat bubble bottom right of your site. I do know the Armories have been a bit weird recently - throwing up fairly regular errors, to me at least, so it could just be an issue Blizzard side.