Data usage

I upgraded my Vodacom phone in November 2014 at the Vodacom shop in Cape Gate. In December 2014 I received a bill for Data usage of R1500.00. I queried this with Vodacom over the phone as this was excessively high compared to normal months prior to this as well as after the December bill for 2014. I requested Vodacom to send me a full breakdown on the data usage so that I can go through it before I pay the account. To date I am still awaiting this information from Vodacom. I get monthly calls from Vodacom (various people) telling me that my account is in arrears and every person I speak to I explain the situation and request the breakdown to be sent to me. When I contact Vodacom the send me to the DATA dept. When I get to the DATA dept they send me to the store where I got my upgrade from when I get to the store they send me back to Vodacom. I have been going in circles for 6 months now. I pay my account due every month except for the 1500 as I requested more information on this issue before I pay. Vodacom cuts off my phone (my phone, my wife's phone and all internet usage that I use for work) because of this. I am utterly frustrated with Vodacom. I need help