Hi, my mom was using data on her phone last night and she is not exactly tech-savvy, so I made sure she was connected to our home WiFi. Anyway, this morning she has several texts saying she now owes 15$ in data usage fees. Why would she be charged if she was connected to WiFi?
Anytime the phone moves away from the range of the wifi (which can happen indoors too) she'd be instantly switched to koodo network data unless you shut data off on the phone or have koodo block it.
It's also relatively easy to inadvertently turn off your wifi connection via Android (notification drop down / some widgets).
There could be multiple reasons.
If you want to be sure she can't have data leakage, turn the data switches off in the phone or call koodo and ask then to block data. You can still use wifi. Just keep in mind that even with wifi you can't send or receive picture messages (MMS) without a Koodo network data connection.