Give new contracts instead of upgrading existing

I upgraded my Giga 20 contract in July 2015. The consultant however did not upgrade my contract, but issued another Giga20 with an open line contract in my name. I have received the device and a new sim card, the sim was never opened or activated. I have repeatedly phoned and asked that the issue be resolved and the second contract be cancelled, to no avail. This morning an upgrade consultant phoned me again asking me to upgrade. When I asked her to fix the problem, she refused and said I had to phone again. It seems that none of the upgrade consultants are willing to assist me in fixing the problem at Cell C, they are all however very eager to upgrade a contract which in my view I have already upgraded. I fail to see how Cell C's consultants cannot understand that there was a mistake, who in their right minds would take out another Giga20 contract when they already have exactly the same contract that is already due for upgrade. I am not prepared to spend more time phoning them to sort it out, as they made the mistake in the first instance.