How to vote more than once in a contest

hello

I'm trying to win a contest here but I can't figure out how they keep track of voters.

First , I tried clearing cookies and changing IP/Proxy to vote again , strangely , it didn't work

Then I tried changing the browser , surprisingly , this one worked. But this can only get me like 3 votes koz i have only 3 browsers.

What I don't understand is how come changing browsers worked and clearing cookies , cache etc and changing IP didn't work ??

Have you encountered this technique…

How to vote more than once in a contest