telkom forcing month to month on an ended contract

i took a telkom contract ended this year may they refuse to cancel month to month the phone is ****** the sim card is suspended becauses of out standing amount why im i being forced to keep doing month to month when im not even using the phone or sim card instead my account is getting higher abd higher i cannot get get another one i have been requesting cancellation since the amount was 2000 now im standing at 5000