MyBroadband conducted a series of tests which revealed that the airtime balance steady declined on Vodacom even when mobile data was off.
The last round of tests found that when four identical smartphones – each with a SIM from a different mobile network – were connected to Wi-Fi with mobile data turned on, the Vodacom and Cell C SIMs were charged for out-of-bundle (OOB) data usage.
Vodacom and Cell C both said this data usage was the cause of the airtime “disappearing” on our devices.
There were trace amounts of mobile data usage on all devices despite being connected to Wi-Fi for the duration of the tests which both networks said resulted in OOB charges.
However, this data was attributed to “OS Services” and was also measured in equal or greater amounts on Telkom and MTN despite the airtime balance on these SIMs remaining constant.
The culprit of this data usage was identified primarily as a “connectivitycheck.gstatic.com” URL owned by Google.
It was, however, odd that the same data usage occurred on all four SIMs and yet only two were charged.
Following this test, we turned the mobile data usage off on all of our test devices and kept the Wi-Fi connection active.
Airtime disappearing with mobile data turned off
We continued to monitor the airtime balances of all four SIMs and found that airtime continued to decline on the Vodacom and Cell C SIMs despite mobile data being turned off.
The table below shows the airtime decline across all four SIMs over three days when mobile data was turned off and only Wi-Fi was turned on.
|Airtime balances over the test period|
|Network||9 Oct||12 Oct||13 Oct|
The My Data Manager app we used to measure mobile data usage did not reflect any mobile data consumption across any of the devices we tested. Neither did the built-in Android mobile data usage tool.
Despite this, both the Vodacom airtime and Cell C airtime balances fell by a further R0.11 during this test.
MyBroadband asked Vodacom and Cell C what had caused this airtime to decline.
In response to our queries, Vodacom provided a breakdown of mobile data usage to various URLs which incurred data charges despite the mobile data being turned off on each device.
The list of URLs was completely different to our previous tests – instead of the trace mobile traffic being routed to Google resources, it was routed to a variety of resources belonging to many companies, including Amazon, HP, Time Warner Cable, Verizon, China Telecom, and MIT.
The company said the disappearing airtime which we experienced was attributable to out-of-bundle data charges, despite the mobile data on the device being turned off.
This is because the issue relates to Android devices that use data across mobile while connected over Wi-Fi, even when the mobile data connection is disabled.
Vodacom said it has replicated the issue and is working with other parties to solve the problem.
Cell C did not respond to our queries by the time of publication.