Hi @RaasheedRaS,

this seems strange, if you go to My Exams, what do you see there?

https://learning.servicenow.com/now/lxp/my-exams 

I recommend you to create a case from the Help Centre on the right side.

Explain your situation and the proper team will assist you with that. Based on what you said you have tried I don't think there's anything else you could do yourself...

Good luck on both registering for the exam and the exam as such!