Vodacom
Still charged for BIS?

In October 2012, I upgraded from a TOPUP 135 contract to the Smartlight 75 with Samsung S3.
I was told that the new contract would take effect from 1 November and that the BIS and old contract thus ends at the end of October.
I have now realised that vodacom have charged me for BIS in November, December and January already. A charge for BIS also reflects on the invoice for February.
I find this completely unacceptable. How can I still be charged for a service that I am not and cannot use?

I except the service to be stopped immediately and to be refunded for the 3 months of BIS that I have paid.
Please have someone contact me as I am not getting any help from my local vodashop.