have been calling vodacom since 29/01/2016,

i had a contract with vodacom and fnb for data bundles.they deducted 99 every month and january 2016 i noticed that VODACOM deducted R798. When i called to complain i was told that my account was upgraded December and the logged a service request for me.they sent me a reference and told me to fax certified copy of my ID and an affidavit ,of which i did but the fax could go through .so i called again and i was given an email address to forward the documents.i forwarded them.even today vodacom has failed to assist me.of which today i called again and i was told that i owe R8000++ and the call center agent advised me to call legal service again monday. please assist me on this