You can vote more than 10 times. Keep voting until you can't. It will tell you that you have "exhausted" your voting rights. It allows you to vote close to 20 times. With one email address.

Try another email address and see what happens. Close and the open your browser if necessary.

Yes, I agree with Sunima. Instead of spending time complaining here, you can help by spending that time (re)voting, or finding others who are willing to spend a few minutes.