British Gas customers hit with bills of up to hundreds and thousands a day are being advised to report the issue and not pay automatically.
Hundreds of households with British Gas have contacted The Mirror to report that their smart meter is charging them absurd amounts for energy.
One customer, Jamie Watkinson-Harvey, described British Gas smart meters as "simply not fit for purpose" and told The Mirror his meter even claimed he was using £2,400 per day.
Energy bills are rising across the country, with households facing increases of £693 a year on average - but some homes with smart meters are being charged even more.
The Mirror understands that the problem might be with the smart meter displays - meaning affected homes will not really be charged the high amounts seen on their screens.
But the good news is that if you are hit with unfairly large bills you can challenge these charges with your energy provider, if the bill is clearly wrong.
Martyn James, of complaints service Resolver, said customers should use their common sense. But if they are being charged energy bills far above the norm, the first thing to do is report it.
James said: "By far the biggest source of complaint at the moment is from people being billed huge amounts for their energy consumption, often after a supplier switch. It’s clear from many of the complaints we’ve seen that there’s obviously a problem as the consumption isn’t realistic or feasible.
"If it doesn't feel right, push back."
James advised customers to report the meter or readings as faulty to British Gas, in writing.
You can also request a check of your meter.
James added: "It makes sense to photo your meter whenever you read it so you have a back up – and with prices so high, to give a reading to the energy firm whenever you can.
"But if all else fails, you can make a formal complaint to the business and go to the Energy Ombudsman if they don’t sort things out."
James advised customers with duff smart meters to tell their energy provider that they will make a formal complaint and get them to confirm in writing that they will not take any action against you until the issue has been investigated.
He added: "Ultimately, if the readings make no sense, it’s for the energy firm to sort out the problem. This can involve sending out engineers to assess the meter’s performance or even a forensic analysis of your bills."
Sarah Broomfield, energy expert at Uswitch, said: “It is unfortunate that customers are experiencing difficulties with their smart meters especially at a time when most are concerned about their bills and want to keep a close eye on how much energy they are using.
“To check if your smart meter is working, your supplier can send someone to test it or you can choose an independent examiner. If your smart meter is faulty your supplier should replace it and refund any extra cost you may incur for this."
British Gas has been approached for comment.
What are smart meters?
Smart meters are steadily replacing traditional gas and electricity meters, and the government wants all British homes to have one by 2024.
The idea is that smart meters track your power usage and bill you accurately, as well as giving live feedback on how much power you are using.
Households found that first edition smart meters were beset with issues. While many homes now have second edition smart meters, which are more accurate, they are not perfect - and many homes still have the originals installed.
James said: "There are way more smart meter complaints than energy companies would like to admit. Smart meters are fallible, and energy companies can - and do - make mistakes."
