Welcome to TPG Community!
We were able to locate your account and reviewed the investigation along with your usage and all is valid.
Our system always provides an accurate result in regards to the data usages of our customers. It is possible that there's a background application which was running on the phone while you were trying to login to your account or else an application is automatically updated.
Here's a community link with "Tips to minimise your mobile data usage".
... View more