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Data usage even when cellular Data turned off

Friendly Neighbour
This is ridiculous. I notice that in my data records within myTelus account it’s showing data occurrences constantly throughout the Night while I’m at home where I have wifi which is also provided by Telus yet somehow I’m logging relatively small amounts of data (usually - but sometimes VERY large amounts) in the middle of the night when I’m sleeping, wifi router is working, and phone is plugged in stationary.

*** I live in a side suite that’s no bigger than 400 sq’ with my 3yr old aka I’m def home by 10:30 every night and out the door in the morning around 7:45 sometimes later***

This has been going on awhile now and so 4:30 am yesterday when I got up I decided to completely turn my cellular data off in settings. Then upon leaving my place later that morning I had to turn it back on to load the web page I was attempting to read while walking to the car. So it was still off. Then I check my data record and it’s says I’ve magically used 8.93MB of cell data at 6:38am.

June 3, 5:23 am - 220.00 MB
6:38 am - 20.00 MB
June 4, 4:36 am - 20.00 MB
5:56 am - 335.39 MB
6:04 am - 260.00 MB

These are only just the most recent examples and those that are more 20MB and above. I have a huge number of other such occurrences just in smaller amounts.

This is beyond ridiculous!

Community Power User
Community Power User

What phone are you using? Some will ignore the setting to download certain updates. 


If you are suggesting you are being billed for data you have not used, the only test for that is to turn your phone off entirely, and allow for differences in time zone between your location, and where the billing is calculated (not always where you are).

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I checked my account and I see a few instances of unexpected data usage (highlighted) but none of any significance. It's possible my WiFi dropped briefly during those times. There is never any usage overnight when I have my phone on and plugged in the charger.


NFtoBC asked you what model of phone you are using but you didn't reply. It's possible your phone is set to aggressively switch to mobile data if it detects weak/unresponsive WiFi. I know I loose WiFi in certain parts of my office so switching to data at the office is not unexpected for me.



This might seem like a silly suggestion, but have you tried removing your SIM for your device overnight to see if any data is logged on your Telus account?  If you give that a try and data usage still appears on your account for your SIM when it isn't even in the device.  My guess is your SIM card might have been cloned somehow.  It might be wise to ask Telus to void and replace the SIM.  

That’s a suggestion I haven’t heard before. I will definitely try this just to see. I’ll keep you posted

Unfortunately in an effort to be "smart", many phones have features that will effectively override your settings. Since you have an iPhone, take a look at the WiFi Assist setting. If it's enabled, it could be the culprit. This is from the Apple Support page on managing data usage:

"If activated, Wi-Fi Assist automatically switches to use cellular data when Wi-Fi connectivity is poor. Wi-Fi Assist is on by default. This might result in additional cellular data use, which could incur additional charges depending on your data plan. You can turn off Wi-Fi Assist in Settings."

I hope that info helps!

Yes that is the go-to suggestion for all however I heard of this issue about 6 months age and it has been turned off at all times ever since. Which is dumb even in itself as I never had this problem prior to this year and have had iPhones for many years while having wifi assist actively on.

Friendly Neighbour
Sorry I totally gapped. I’m one the iPhone X and the wifi assist has been toggled off since Early March.