The energy regulator has revealed new rules for household suppliers that include priority help for vulnerable customers struggling to pay their bills.
Ofgem said that from December, gas and electricity providers had a duty to put those customers first when contacted with an enquiry about their payments.
The new requirements also force companies to contact customers directly if they miss two monthly or one quarterly payment.
The watchdog said support, such as affordable payment plans or even repayment holidays, if appropriate, should be offered in the event aid is needed.
The new rules are the latest actions taken by Ofgem in a bid to improve communication between energy suppliers and households amid frustrations around customer service at a time when bills remain punitive due to high wholesale charges.
A report by the price comparison site Uswitch earlier this week suggested that 3.2 million households were behind with their payments heading into the winter months.
There are warnings that the next energy price cap review will see average annual bills rise back above £2,000 again from January, reflecting higher wholesale costs as demand ramps up for the northern hemisphere winter.
Ofgem has threatened fines if customer service expectations, which are written into a company’s operating licence, are not met.
Its chief executive, Jonathan Brearley, said: “With recent global events increasing pressure on gas prices, it’s likely that bills will rise further.
“This is why the industry needs to do all it can to ensure good customer services and provide help with managing debt, especially for the most vulnerable.
“In the last year, we have seen some good examples of suppliers stepping up their support for customers. However, despite this, the feeling of those on the frontline working with vulnerable households is that more still needs to be done.
“Long wait times to speak to someone on the phone. Letters not replied to. Lack of empathy for people’s personal circumstances.
“This needs to change and today we are setting out our expectations of suppliers this winter, and how they will be held to account to ensure consumers can get hold of them more easily.”
As part of the effort to encourage good customer service, suppliers will need to publish the Citizens Advice ratings so the public can see how they compare on issues such as call wait times and quality of responses.