Being placed under debt reiew without consent

On the 15th October I received a call from Lynn at Debt Masters. She explained her product and offered to assist with reducing my debt. She mentioned that only once I receive the relevant paperwork and sign those documents will the process continue further. To date I have not signed any documents so what right do Debt Masters have in placing me under debt review without my consent? I have been recieving calls from my credit providers informing me that my accounts are blocked. This has caused me alot of unnecessary problems as I have to explain to these providers and still try to get a hold of Debt Masters. When I finally got a hold of them I was told to complete a cancelation form and make a payment of R500 to clear my name. Why should I be doing this when I did not give them consent in the first place to go ahead and place me under debt review?