Dear friends i was using the plan 125 scheme of bsnl broadband.I had given an application to upgrade my scheme to 250.Now my plan change is provisioned from 26th May,2009.I had used about 420MB before the plan change ie from 1st May,2009 to 25th May,2009.From 26th May to 31th May,i had used about 500MB(1 GB free usage).Pls calculate my bill.Does the 420MB used before the plan change calculated as the free usage of plan 250?