Sheela,
7 days before your exam simulator expires you will receive an email with instructions and links to extend by either 30-days or 60-days. So if you still have > 7 days on your subscription then no need to take action. But if you are < 7 days then you may either find the email in your spam folder, or you can - as Harry suggested - contact This email address is being protected from spambots. You need JavaScript enabled to view it.
Good luck on your exam!