MTN then went on to list other possible reasons for customers’ data disappearing. These include continuous automatic updates from applications such as Facebook and Instagram that run in the background ...

In a statement, MTN explained that data can be quickly depleted if customers, for example, have LTE-enabled phones, apps that run in the background and continuous automatic updates from applications.

Restrict Background Data Usage - Android ... And if someone buys you MTN data during this period, just know that they truly love you!

MTN’s press release on “disappearing data” is reproduced below ... smartphone now also allow apps to function / work in the background regardless if you are using them directly or not.