i just want out, and nothing more to do with vodacom

why is it such a mission to exit a contract that has matured, being forced on a month to month against my will is not fair business practices. being offered a settlement discount on my account in writing, then once the amount is paid up, The discount is not factored in, sawing the account is still owing even though the discount offered was in writing. even worse services are resumed and billing continues despite wishes to exit the month to month contract. why is requesting a paid up letter and cancellation of the contract such an impossible mission with vodacom?