INCORRECT BALANCE

To MultiChoice I had my decoder installed last month and I was asked to phone in and register so I could select the package I would be able to afford, I phoned in and activated my account and I SELECTED THE FAMILY PACKAGE which I was told is R235 and now when I went to my account to make a payment it says I owe R692.58. HOW IS THIS POSSIBLE????? I was told I would only pay R235 every month. PLEASE SORT THIS OUT URGENTLY!!! this is very upsetting as I can only afford to pay R235 as I had said when I activated my account.