Duplicated Fibre lines - need a refund

I changed my speed line in July, and the sales rep who assisted me opened a second line for the same address. Looking at the invoices, it was 3 lines to start off with. From paying R 839 I changed to a R 699 line. But I was charged R 2250,41 in September and subsequently R 1518 October & November billing periods. I need the cancellation done and the money refunded.