Billing me for something I did not order.

I received an email from Vodacom billing me R 837.73 for a new product that I did not receive and I did not apply for. I am currently paying R 179 for data contract I took a while back and the contract will come to an end in August. I decided to phone them today and I was told that the order was made at one of their stores. The product is apparently an Iphone. I was advised to either to phone their forensic department(they did not pick up their phones) or go to a police station to make an affidavit(which I refused as it is not safe). I am dissatisfied with the way Vodacom is handling our personal information and also refuse be inconvenienced.