DISAPPOINTING SERVICE FROM VODACOM

I AM TOTALLY DISSATISFIED WITH THE SERVICE RECEIVED FROM VODACOM. AND I HAVE BEEN PATIENT AND GIVEN THEM AMPLE TIME TO RESOLVE THE MATTER, BUT THEY DO NOT SEEM TO CARE. HOW DOES A CONTRACT GET RENEWED/CHANGED WITHOUT THE CUSTOMER'S CONSENT. I HAD A CONTRACT FOR 90GIG DATA, ALL OF A SUDDEN APPARENTLY I TOOK OUT A CONTRACT WITH A HANDSET (WHICH I AM NOT IN POSSESSION OF) I NOW GET LESS THAN THE 90GIG DATA THAT I SIGNED UP FOR, BUT THE DEBIT ORDER AMOUNT THAT GOES OFF MONTHLY HAS INCREASED AND THE CUSTOMER DID NOT AGREED TO ANY OF THAT. VODACOM PLEASE GET YOUR HOUSE IN ORDER, WHETHER THIS IS A CASE OF ***** OR JUST NEGLIGENCE BY A STAFF MEMBER, YOUR CONTROLS ARE OBVIOUSLY NOT ADEQUATE AND EFFECTIVE, HOW DOES A CUSTOMER'S CONTRACT CHANGE AND YOU ISSUE OUT A DEVICE AND EVEN CHANGE DEBIT ORDER AMOUNTS WITHOUT CHECKING WITH THE CLIENT? VERY DISAPPOINTING SERVICE FROM A GIANT OF A COMPANY LIKE VODACOM!