TERRIBLE CONTRACT TERMS

How can you keep someone liable for a contract after the period has ended? I have requested on several occasions not to continue as I cannot afford the increased premium. They refuse to cancel my contract that is now on a month to month basis as I need to pay the arrears first. All I want is to cancel the contract then I can pay off the areas how is this so difficult to understand. I cannot afford the increased premium thus CANCEL my MONTH TO MONTH contract as requested!!!