Cancel the contract

Vodacom Chatz Eastgate are refusing to cancel my contract. I went in store on the 16th August and enquirers about a data package, to my surprise I was told it was immediately approved and would be activated the same day. The next day I received feedback from work that we would be getting salary cuts. I returned to the store and tried to cancel. I was advised that the contract is not yet active and I would only be able to use the device (router) after the debit order at month end. Subsequent to this the store has advised that they cannot cancel the contract but customer service says I should be allowed to cancel under the circumstances. Apparently the policies differ from store to store??? Vodacom please cancel my contract, I have not used the device and I am not being unreasonable. Why should I pay a cancellation fee for something I have not used???