Hello Aspirant,
Yes, you can call them and you can also write an application to them telling them that two of your exams are getting clashed on same day. Maybe they will provide a solution to your problem but the chances are low that they will reply to your query as the student help panel is not that active. You can also mail your query to them.
For further information, you can visit the following link:
https://ugadmissions.iiit.ac.in/ugee_page.html
All the best!
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile