Expiration of Unused Data

So, I see that Cell C has an advert out that before your data bundle expires you can dial a number and then you don't lose any unused data. <br> <br> Is Vodacom going to be doing the same, or is it time to change my cell phone provider for both our phones and tablets. Between all the phones and kids tablets we as a family go through loads of Data a month, and if I can save by not losing any data, then why ever not ???? <br> <br> Besides, its utter ******* anyway that I lose something I have PAID FOR. Pick n Pay don't come and take away the unused groceries at the end of each month, why should I lose my data? I am off to Cell C as soon as I finish work to find out how this story works.