Sudden, huge data use

[LH1971]

My data allowance resets on the 19th of every month. I have a 20GB allowance, and I usually barely use a quarter of that. Yesterday - 19th March, the first day of my new month - I get a warning from O2 that I've used 80% of my allowance and have under 4GB left for the next four weeks. Whaaaat?! How is that possible? If this is a fault, I need it to be fixed ASAP. Help!

[pgn]

Guide: Help make your data allowance last  might give you a pointer or two, @LH1971 - come back if you have more questions.

[LH1971]

Thank you, but I simply cannot have used nearly thirty times the amount of data that I normally get through in the space of one day. This has to be a fault at O2’s end: surely. 

[pgn]

Your phone and your MyO2 will show you what spiked the data usage this month, @LH1971 - see how the two tally, if O2's side is wrong, reach out to O2 via Social Media, links below this post for Twitter, Facebook and Instagram, they should be able to help.

MyO2 help here: Guide: My O2 - Allowances  

[MI5]

Let me guess you have an iPhone? @LH1971 

[LH1971]

Thanks, all. Yes, an iPhone. But I've never used as much as a third of my data in one month, let alone nearly all of it in *one day*. Surely that's next to impossible?

[MI5 · Accepted solution]

@LH1971 

It's a recurring issue with O2 and iPhones.

It's not happened for a while but there's been a few just recently again.

You need to moan to O2 about it which of course they will deny there's any issue, but at least if enough people report it, something will be done about it.

[LH1971]

Thank you. I shall moan!

[pgn]

This is an old, but perhaps still relevant, iPhone and data guzzling answer, @LH1971 - if it helps?

https://community.o2.co.uk/t5/Apple/High-data-usage-on-iphone-5/m-p/513858/highlight/true#M109278

[LH1971]

Thanks. The only possible culprit could be Apple Music, which I'm a new paying member of. I've turned off its access to mobile data. Now all I need is for O2 to be nice to a customer of 25 years and simply give me back the data that I didn't use last month.