@vishalrao,This issue was discussed several times before. Even if the portal shows "Provisioned" for your new plan, the effect in billing cycle always happens from the 1st of the following month. You will however note a speed change according to your new plan but the new billing generally happens from the next month. This issue happened with me when I changed from Home 500 to Home 750 UL. The portal showed "Provisioned" for me from the 12th of the month so I assumed that I was on a UL plan but was later shocked to see a huge bill the next month. Luckily, the amt was not huge. Anyways, I am not sure if BSNL still follows this policy.