cancelation of contract

Vodacom Direct contact me and offered me a wifi modem on contract. I received the parcel but then phoned Vodacom to notify them I cancel the contract (reason : got better wifi deal with Telkom) and they arranged with the RAM company to collect the parcel. The parcel was then received by Vodacom on 20.03.2015. ON 24.03.2015 a debit order of R183.80 went of my bankaccount. As I was not aware of that there was unsufficient funds in my bankaccount. I had to pay R125.00 unpaid fee. I phoned Vodacom and try to explain my dilema and they told me they did receive the parcel and the order will be cancelled. On 24.04.2015 a debit order of R542.80 went of my bankaccount again and same story there was not enough funds so my bank charged me R125.00 unpaid fee again. Since then I am struggling with Vodacom. They told me today that an email was send on 06.05.2015 to confirm the cancelation. My problem is I want Vodacom to refund me the R125.00 x 2. The debit orders was unpaid so I dont need refund for that. Regards Carene Passerini