Cognizant Technology Solutions — some buttons are not working in portal

I attended cognizant technology solutions interview this month through amcat and got the offer letter. As a part of pre joining formalities we need to upload our photograph for the id card. The browse button isn't working no matter how many times i try. Even my friends are also facing the same issue. We need to submit all the details in a week's time and there is no way we can contact the team.