Please keep in mind that while you are able to run a test site, things would be limited or no support on test sites. In instances like this, if we started out on your test site, we would need to apply the same effort on your live site thus doubling our efforts, but your visitors would still be impacted by the same downtime as if we started on your live site.
What we can do, to minimize that downtime is at 8am Eastern tomorrow, you can set this up and our team would be able to put this in our queue the second you hit an error.
If you get your access details sorted now, that will also help speed up the time between efforts.