I suppose the Celcom customer may have downloaded some paid stuff's from websites which had cost him that much. The unlimited 3G data browsing is only for browsing bytes and not downloaded stuff's.

The customer may lodge a complaint to seek more detail what the customer has done, just browsed or downloaded payable stuffs via the net.

If found fault, Celcom shall rebate back or if not at fault, the customer had to bear the amount.