Telkom mobile contract still charging me for 7 month after sending the cancelling request multiple times

HI

I am had telkom mobile contract and i have sent a cancellation request in month of October 2017. But the cancellation was not done and i was getting charged for it. Then i sent it again in Feb 2018, but i was still being changed and then i sent the form again on request of the call centre people again in April 2018, but i am still getting changed.

I am now planning to file a court case against them as them charging me even when the cancellation form has been sent multiple time.

Thanks