Billing

I app**** for rain home wifi and the terms and conditions werw not explained to me. I was only told that its a month to month payment plan and in mind i thought you pay and when you skip a payment the service will be switched off. I skipped a month and the service was switched off within days and little did i know that the money accumulates. I called the agent for further information but instead I was confused more. My question is why are they switching it off and yet the money accumulates? What am i paying here, im so annoyed