No service but still being charged and no end to a cancellation

In October 2017 I send my application for cancellation of all my services, the reason was I was not able to access my internet, no service most of the time. To-date I am still trying to cancel my services, I have made several calls to the call center who informs me the service is cancel, then another month starts and a new bill is sent to me for service which I cancelled months ago, When will Telkom do this right by cancelling my services, I have done all they requested, each month the bill is escalating. Please help