Cancellation of account

<p>I agreed to a data package from Vodacom thinking it was additional data for my phone. However I received an external modem, which I did not want. I returned the modem immediately and requested the data package be cancelled. I have now spoken to the after sales team 3 times for this to be rectified. I was ensured that this was the case and money that was deducted from my account was credited to me in the previous month. However I have yet again received an invoice for the data package. Please advise what I must do in order to finally stop these deductions. Please do not refer me to the after sales team yet again as they are clearly not able to rectify this problem. </p>