What ever happened to broadband option 1, I never download anything on pc yet I am being charged for going over my 10G usage allowance, how????
1. Malware sending stuff you're not aware of. Do a full anti-virus and anti-spyware scan.
2. Using more than you realise. Watching videos; using Skype; downloading updates for software.
3. Someone else using your WiFi. Make sure it's secure and maybe change password.
I find it hard to exceed 10GB without knowing. I do email, browsing, a fair bit of online gaming and the odd iPlayer program, and I usually stay around 3-4GB/month. So something is up if you go beyond 10GB and don't know how.
if your router has not reset in the 3 days what usage it shown?