It is a frustration for prepaid user when the allocated quota has been completely utilized resulted in slow or no network connection. However, Digi has recently introduced a new feature that allow users to buy extra data in YouTube, WeChat and Twitter without interfering your current app activity. To purchase internet add-ons in each app, simply click on “see more option” as shown in the videos below.
Currently this feature is only available in these 3 apps. As for others, you need to head towards MyDigi App to subscribe for internet add-ons.
Source : lowyat.net