A family member who is on a £5 a month SIMO plan recently got their latest bill and it was for over £100. As you can imagine it was quite the shock.
I've read through a breakdown of their bill for the month and I keep noticing £3.00 internet charges of a couple of Kbs once every day and mostly at ridiculously early morning hours (eg 4am) at first I thought it might be app updates where they had not been connected to WiFi but then I realised they had internet usage listed an hour later at £0.00. I'm wondering if it is a rogue app or something they've subscribed to but if that's the case aren't those subscription services usually either done via a debit/credit card or through premium SMS messages?
@Smush, yeah so the likely culprit is "background data" where apps still send tiny amounts of kb through mobile data signal even if on WIFI. If this £5 SIMO doesn't have a data allowance, I would recommend getting some data. Some phones have these tricky settings that allow the phones to automatically toggle between Wi-Fi and mobile data, some have a "data saver" option to completely shut down background data usage. You're probably going to have to look into that for your own make/model handset, but it's just easier to get more data on your SIM. The £3 is a data charge that covers you for the day, that's why you are seeing it only once and then £0 for the rest of the data access for that day.