Consumer being underbilled over a long period in spite of the meter recording the consumption correctly -- Fact of underbilling discovered during meter testing -- Bill raised on the consumer for all the unbilled units at one go -- Held not a correct method of billing and raising demand -- Ordered the apportionment of the units to the entire period from which the service connection was released -- Ordered that demand for the unbilled units to be restricted to a period that is no more than two years prior to the date on which the underbilling was discovered in accordance with section 56(2) of the Electricity Act