Threatening handover

I cancelled my contract in May 2015 and asked for a device settlement amount as massive amounts were debited from my account. Even though receipt of cancellation was acknowledged, the debit orders continued. After months of investigation I discovered a cloned SIM operating under my name which I was being billed for. I reported this to Cell C over a dozen times yet every month I received threatening calls to make payments. Eventually at the end of 2015 I finally received a device settlement amount but when I asked for bank details and a reference number, I was again ignored. Yesterday I received an sms stating that I am to be handed over for debt collection.<br> I also requested the contact details for a representative to receive a letter of demand and the subsequent summons as I have incurred financial losses far in excess of the settlement amount. This request was also ignored.