Paying for contract that I returned the phone back

I was approached by Vodacom with another contract which agree in December however when the phone was delivered I was not happy with the phone. I therefore requested them to come and collect it the consultant that was helping then she told me she was out of office for some therefore we agreed that she will send drivers to collect it and it was collected. End of January i received my statement indicating that they deducted the R199.99 x3 (DEC twice and JAN). When i phoned vodacom they told me I should write an affidavit to indicate that I do not have the phone with me so that they can reverse the amoount, honestly I do not have that time because their system should show that a client returned the good. so my complain is for Vodacom to reimburse my money.