On my Vi Prepaid, I am on Rs 459 Plan (old rates), having 6GB data and 84 days validity. Now, if I recharge with Rs 155 (1GB Data, 20 days validity) before the expiry of Rs 459 plan, will the validity be extended, i.e. will I get the full 84 days + 20 days, or will I lose validity of the existing 84 day pack?