how to remove duplicate votes

Using YOP poll free. First poll. Results are skewed because some IP addresses voted multiple times.
1. How do I remove those extra votes? I have tried trashing the logs but they’re still in the results. I have also tried de-authentifying them in the Votes, but still there.
2. How do I ban those IP addresses from voting again? Nothing works in Options/Settings/Access
I have already searched this forum but found nothing that works for me. Thanks for any suggestions.

The page I need help with: [log in to see the link]