If your meter is declared defective, you would be receiving an assessed bill based on your consumption during the corresponding months of last years, that is estimated bill due to faulty meter at your premises, which should be replaced immediately. It is the policy of IESCO that on observing a defective meter, a “ Check Meter ” is replaced immediately, so that correct electricity consumption is measured correctly. But, if due to any reason, ‘Check Meter’ is not installed, you will receive an estimated bill marked as “ def est ”. You should contact your subdivision office if your meter is not changed within three months.