Why can't anyone fix my bill?

Between October and November, my bill nearly doubled, from $85 to $150/month. I've been trying the past 2 months to get someone to fix it. I have not paid the new rate because it's absolutely not what I signed up for. Now I'm told my account has been locked due to no payment, and the only way I can get anything changed is to make a payment. Why on Earth would I make a payment when I'm getting overbilled? Additionally, they billed me for yet another month yesterday, and when I call to cancel service, I'm told I have to make a payment in order to cancel my service. Additionally, they've hung up on me twice after explaining my predicament five or six times to different people and being bounced all over departments.

This is, without a doubt, the worst customer service experience I've ever had.