Pathetic customer service - Corporate *******

Pathetic service received. Their marketing department phones me 1 day to offer a 1 gig deal which at the time I required and the following day another person phones with a better 20 gig data option at the same price. I tell them to cancel the 1 gig as I would require it due the 20 gig making more sense (this is also within the cooling period). They don't cancel the 1 gig and been charging me for both sim contracts the last few months. I phone to enquire about the charges, where they admit to not cancelling the 1 gig contract. They initiate the cancellation but still charge me for the contract I never wanted which is actually *****ing money form me and then refuse to refund the amount ******. just horrible customer service.