Auto voter? I find it hard to believe that someone would go through the trouble of voting for someone for 2 years straight.
So ya'll are on the same router and if they vote they take it from you. I recommend voting on a mobile device. It lets you vote since it's from a different IP. Unless someone is voting for you on a dif server.
I just went and voted for Mineverse for you and it went through. Someone on your home wifi connection must me voting for another server and it is saying that you already voted for that day. Even though you have different usernames, it uses your IP address to determine if you already voted for the day. If you have a cell phone that is not connected to your home wifi, try voting from that and see if it will work for you. It must have a different IP address from your home wifi.
It used to happen to me too, when I nearly got top voter, then at the last few days someone voted to get me lower :( It's been a problem for a long time, but I hope you figure out your problem @Valixta . I would suggest trying to follow the tips given by @Dyna_Mighty