Dear aspirant,

I'm sorry that you are forced to go through this problem. Unfortunately, there is nothing much you can do in this situation. I would suggest you to keep trying to get in contact with them somehow either through phone or mail. If they consistently don't respond, then you should try and ask anyone from your colleagues about the exam. There really isn't much else you can do. Try to follow instructions given to you about the exam earlier.

Hope this helps!

Good Luck!