MY ACCOUNT BEEN DEBITED FOR A DEVICE I DONT HAVE

I BEEN A CUSTOMER OF TELKOM MOBILE FOR OVER 3 YEARS, I CURRENTLY HAVE 5 LINES WHICH IM USING INCLUDING DEVICES...... WHIST GOING THREW MY STATEMENT IT CAME TO MY NOTICE I BEEN PAYING FOR A LINE WHICH I DONT USE, IN MARCH 2014 I REPORTED A CELL PHONE ****** AND IMMEDIATELY HAD THE DEVICE AND LINE BLOCKED, AND I HAD INSURANCE ON THE FONE..... I BEEN PAYING FOR THIS CONTRACT SINCE 2014 UNTIL THIS VERY DAY IM STILL BEING DEDUCTED.... THE CONTRACT BEEN UPGRADED LAST MONTH AND WHEN I WENT INTO THE STORE NOBODY CAN ANSWER ME AS IN WHY ARE THEY BILLING ME FOR A LINE I DONT USE NOR CAN THEY ANSWER ME HOW DID THE LINE GET UPGRADED...... I INTEND IN ENGAGING A LEGAL ADVISER BECAUSE I FAILED TO GET ANSWERS FROM THE SERVICE ADVISERS IN THE STORE.... ALL THEY CAN TELL ME IS THEY DONT UNDERSTAND WHY IM BEING BILLED... SO NOW WHO DO I ASK ???