Cancellation of Contract - not actioned

My cellphone contract with telkom mobile was scheduled to end 23/10/2015. In terms of the contract, at least 30 days notice was to be submitted. I did comply with this submitting my cancellation docs on 21/09/2015. To date, the cancellation was never actioned. This now holds me back from getting another cellphone contract & to port my existing number. I've been phoning the customer service number daily & I repeatedly get the message that I will be contacted by the cancellations/Retentions department but it has never happened.