The meter should be running at 4 pence per kilowatt hour if you are using £10 per day for 20 hours would be 50 pence per hour when it should be 4 pence per hour this will apply to both pay as you go, or credit meter.so failing to set the meter correctly.
I am looking at the reviews on your company each showing the same story, claiming the phone is stolen when a check is made of the imei number shown this clean