not reacting on request to cancel landline

I went to the Tygervalley branch in February to request a cancellation of a business landline. The request was logged on their system and I was told the request will be received by the appropriate cancellation people and the line will the terminated. Needless to say I'm still receiving an account for this line which needless to say has not been cancelled yet. I went into the branch again yesterday to complain and was given the reference number of the cancellation request logged as well as the date it was done - 24 February 2015 ! Its almost 2 months ago !!!! I am not paying for a line that should have been cancelled already !!!