If you have an electricity meter fitted at you home, we are not responsible for its upkeep or its repair. If you experience a problem or a fault with your meter you must contact your supplier.
Electric meters usually have £3-5 of emergency supply on them. Should you run the meter completely out of credit, when you 'top up' your payment card, the first part of your payment will repay the emergency credit you used. Any remaining will go on as you normal allowance. People often think there is a problem with the meter, when in fact, they have not allowed for the emergency credit to be taken from their payment first.
If in doubt, contact your supplier.