BILLING FOR HANDSET - ONLINE UPGRADE

I HAD UPGRADED MY CONTRACT 3 MONTHS AGO, ONLINE AS TIME IS PRECIOUS. EASIEST 5 MINUTES EVER. NOW AFTER BILLING ME r488.51 FOR 3 MONTHS, NOW ALL OF A SUDDEN I RECEIVE A BILL FOR MY ONE LINE FOR R2729.98. THIS, AFTER NUMEROUS PHONE CALLS AND BEING SENT FROM PILLAR TO POST, IS APPARENTLY A \ONCE OFF"HANDSET FEE. NONE OF THIS WAS DISCLOSED ON THE WEBSITE WHEN UPGRADING AND I FEEL TOTALLY *****ED OVER. I DON'T HAVE THE FUNDS TO PAY THIS TOO"