No Refund

I was over charged at the end of December and was told that this happened to a lot of customers and that they will refund me. However, I had to relog again at the end of Jan because I still have not received the refund. They said it will take 2 working days yet still nothing. This is so pathetic of Vodacom for overcharging and not refunding the overcharged amount or subtracting it from the new month bill.