Taking me for a ride!!!

I moved to NZ during Oct 2014 and obviously I don't use my Vodacom sim card anymore. During Nov/Dec, according to Vodacom I used R3 000.00 worth of data even though I can't use the sim. I requested information from them w.r.t. the usage, date, time, web pages visited but never received the info. I eventually settled the account of over R5 000.00 as I do not want to be in given over to debt collectors. When I made this payment I requested, in an email, that Vodacom must inform me of the total amount I must pay to stop this contract with immidiate effect as I was afraid that I would be charged again for a service that I don't use. To date I have received no reply from Vodacom. They were very quick to demand that I pay the (false) outstanding amount but now that I require that they stop the account I get no reply.