DEDUCTING R1848 FOR WHAT??????!!!!

Telkom just deducted a R1848 from my account for WHAT??? I FOLLOWED ALL THE PROCEDURES TO CANCELLING, GIVING A MONTHS NOTICE. STICKING TO MY CONTRACT, I WAS DUE FOR AN UPGRADE SO I WAS NOT IN BREACH OF CONTRACT. PAID MY INSTALLMENTS ON TIME ALWAYS! WHAT IS THIS FOR TELKOM??????