How do you even let the Club know when there's an issue? If anyone tries to tell them, they just dismiss you as an idiot user.
I see that the site is now down until 11:00 re-routing to Queue-It. I don't know if that's for another sale or if they are working on the issue.
My purchase seems to have gone through, despite the error messages. After clearing cookies, I was able to get back in a few times, but generally couldn't proceed more than a couple of screens. I was able to see that most seats had now gone, so that suggests most people did manage to purchase, which is worrying. Based on experience, the Ticket Office have absolutely no interest in fixing issues if they only affect small numbers of members.