Can not view my exam appointment in Future GMAT Exam section

Hi,

I did.
However I did face another problem. Half an hour before the exam I was able to see the 'begin exam' option. I did click on it. I cleared all my check-ins. I received a message on the chat option that my check-in process is complete and they are letting me in the exam and told me that the proctor will join me shortly. However, nobody came. All I could see was a black screen with a small tab on the top-centre of my screen which was recording me, a chat option and a whiteboard option. I waited for half an hour and clicked on the chat option but it was inaccessible. I waited for the proctor to come till 06:00 IST (one hour from the time my exam had to start), yet there was no response whatsoever but a blank black screen.
I then contacted my regional helpline number and they said they are closed now. I also dropped a mail to GMAC APAC and the customer care but haven't received a response yet.

What should I do now? Whom should I contact? Will I get to give a re-exam?