Contract not cancelled after settlement paid

On the 9th of January 2015, Areplacen, from the Customer Services gave us the settlement of 4,422.95. We had to write the letter to cancel the contract on acc no: 1.***8, the number and sim card should be retained as prepaid agreement as from 9 January 2015 (cancellation date) It was supposed to take 7 days. I confirmed with them, they received the letter and proof of the payment. I then received another invoice and after phoning at least 7 times, I found it is still not cancelled. Each time a different consultant, new reference number and \story". they just pass the buck and Lerato (cancellations) put me to Nokuthula who told me that I have paid the 4"