Vodacom clear my name

I took a router last year July from Vodacom the sales lady said it’s 30g which 15g a day and 15g at night, when I receive the router to my surprise the router was 10g I called them the following day and wanted to cancel, they say they are going to come and collect it, but they were still deduction for the router that I don’t even use them I disputed the debit order , every time when I call them they say they will come and collect it but they hadn’t stop deducting my money and they only collected the router in November and now this is affecting my credit score coz now on my credit it says that I owe Vodacom which I don’t understand why I owe them coz I did not even use the Wi-Fi router