Unhappy customer

Earlier this year I app**** for a contract phone with vodacom and I was approved. After sleeping on it I realise that I won't be able to afford the contract, I then called vodacom to cancel the deliver. I was assisted and notified that the contract and the delivery was canceled. A few days later the courier company came to deliver the devise and I communicated with the delivery guy that I have cancelled the contract and the delivery of the phone and I Did Not Take the package I turned it back

What then surprise me is that I am receiving call and emails saying that I owe the account, and the bills has accumulated to above R12 000!!! With all these calls I have to explain myself, however I kept being harassed. The "R12 000" also amazed me because on the statement I received they say R0,00

What is also frustrating is that I have now been handed over and my credit score has been dented