no unsubscribe option in my manage page

i received my SIM yesterday and activated my plan (data only since i wanted to use add-on for voice and sms). but my phone shows me that there's no service and i cannot register on the Fizz network either automatic or manual. and beside there's no option in my plan manage page except "Add User". i really want to unsubscribe during my 15 days trial and get refunded and i'm completely dissatisfied with the service you are providing.