Billed twice

I tried to activate a data bundle on my account and received an error message. I tried this again and received the same error message and had to try again. On the third try, the transaction went through, but then activated 2 three gigabyte bundles while I wanted one. When I called Cell C, the consultant refused to cancel the other transaction, saying its not possible as I activated the bundle and will therefore have to pay for it. I refuse that I activated two transactions and I don't believe that I should have to pay for glitches in Cell C's systems. I certainly will not pay this amount and if its not sorted by soon I will simply either cancel my contracts and move them to another network along with all my numbers or just cancel the debit order on my account. Either way, I refuse to pay for what I do not want and did not purchase. I CATEGORICALLY REFUSE>