invoiced for cancelled contract

I cancelled my vodacom data contract that on the 3rd June 2015 and the consultant who was helping me said the final deduction would be on the 30th June 2015. The contract was cancelled and converted to pre-paid and i was invoiced R0.00 amount in July 2015. <br> <br> I am suprised Vodacom invoiced me for the August 2015 month when the contract is cancelled. I called *** and I was told to pay and threatened with legal service.<br> <br> Do you always threaten people with ITC when they cancel the contract? the number:***