Telkom don' t cancel contract after numerous queries

I have send my cancellation documents to Telkom on 15/03/2017.It is for my fixed Telkom line with number ***.I am with Telkom in contact on a weekly basis.They just told me they escalating the enquiry and then nothing happened.My account number is ********** 40001.Telkom keep sending me accounts which I am not goint to pay.