No Response from 26/04/2017 for cancellation of contract

<p>I signed up for a 24 month laptop contract in May 2015 with Telkom and was double debited in the first month and was told that I would therefore not be charged in the last month. When calling to confirm the cancellation of the contract in April 2017 - I was told that I had to give 21 days notice to cancel the contract - so i had completed the relevant form and had sent in my notice on 26/04/2017. i was then debited on 02/05/2017 (for the contract price) and 31/05/2017 (additional charges) and now recieved and invoice to be debited again on 30/06/2017 ( for the contract price of R289 plus additional charges which I have never seen before adding up to R358) - whereas the contract is supposed to have been terminated already. I had made numerous calls to the call centre and all that they can tell me is to wait and they will debit me until the contract terminates - and the amounts can vary from month to month - which they cant provide an explanation for. I find this unacceptable - Am I supposed to be paying indefinitely for a service that I am not using which fluctuates in premiums that should have already been terminated already???</p>