Cell C fibre taking money, without me using their products

I orderd a fibre line with cell c, when they delivered the router and the free sim card I called them for activation. They then realised that they are not authorized to provide fibre in the complex that I live in, so the contract had to be cancelled. They sent a courier to come and collect the box and the sim card. The sim card wasnt even opened from its plastic yet, now Cell C deducted R995.32 from my account for using one of their products. I spoke with one of their imployees on the phone and they said it was for using the sim card. The sim card that wasnt even opend !! This is ridiculous and unacceptable!! Stay as far away from cell c as possible!