Unfortunately, for most tests on our system you won't be able to log back in if you have closed down or refreshed the page during completion. To have your testing reopened, you will need to contact our support team by clicking on the "Submit a request" link at the end of this article.
In your request, please mention that your test has been closed during completion as well as a screenshot of the page you are stuck on - as it will speed up the process in solving the issue for you.