Probably best to use the iD Live Chat service to dispute the data usage, ​@Davestephenson. 

Nobody in this public Internet forum can access your private iD account. 

Hi ​@Davestephenson 

Thank you for getting in touch. I completely understand your concern it must be confusing to receive those data usage alerts, especially when you usually use much less than your allowance.

Sometimes, data usage can update with a short delay, meaning older usage may be processed all at once and appear higher than expected. To help us investigate this further, could you please confirm the following:

Whether you’ve recently used your phone as a hotspot or downloaded any large updates or apps

If you’ve been roaming abroad or using mobile data instead of Wi-Fi recently

Once we have this information, we’ll be able to check your data usage in more detail and determine if any errors have occurred.

Alternatively, please send us a private message so we can look into your account directly. You can reach us via Facebook, Instagram, Live Chat, our community page, or by emailing socialqueries@idmobile.co.uk. We’d really appreciate the opportunity to put things right for you.

Thank you,

Zandile