I had an upgrade and renewed my contact in November through carphone warehouse. I used to have 2GB data but the new contract gave me 4GB. In December I had a text notification from O2 saying I had used 80%of my data even though I hadn't been using it more then usual. I assumed it was an issue with the change of one contract to another but it has happened again this month, even though I am only 20 days into the billing month. The data usage on my phone is saying I have only used 815MB so I'm confuse why O2 is saying I've used 3.2GB. Has anyone else had this issue?