Very interesting concept, to create such an index. I am an IT consultant and can help you in enabling this survey.
In my opinion, you can use site like survey monkey, however, if you want an authentic information, you should build an app or website.
However, can you please suggest, how would you ensure that respondents would not be biased as 500 is a very less number. I think you need to create an app to have multiple survey to different people at different time to remove the bias.
I am not expert at creating survey, however, I think would be very good at analyzing the problem and suggesting the solution.
In the mentioned price, I will help you to create the right strategy and survey question.
Many Thanks,
Shubham