Double charging a 1GB bundel then not reversing the order but sending a message saying the purchase will only be charged once

On the morning of the 7th of January I used the my Vodacom application to purchase a 1GB data bundel. After the purchase i noticed my accout was charged with double the amount as advertised. I phoned the call center to explain to them i only require 1GB other wise i would have chosen the 2GB option the same day i received a sms saying the matter has been resolved however the money did not reflect. I believed that it will take time to reflect so i waited. They still have not returned my money or deducted their 1GB exstra data bundel...is this theft as im forced the pay for something i did not want? Please assist. My Vodacom references are ********** 3 and 1- ********** **********