Some 3,626 complaints were made in February 2014 alone, a 252 per cent increase on complaints figures for February 2013.

Chief energy ombudsman Lewis Shand Smith said: “We’re witnessing a record level of complaints relating to the energy sector as the cost of living debate continues to dominate headlines, which is evident in the 252 per cent rise compared to the same time last year. Issues relating to billing in particular were a major source of frustration in February as consumers become more aware of their entitlements and are less likely to settle for poor service.”

The most common complaints were not receiving a bill (700 complaints); disputes about billing charges (439 complaints); the quality of customer service related to billing (413 complaints); and inaccurate invoices (361 complaints).

In February, regulator Ofgem estimated energy suppliers owed £202m to former domestic customers. That month complaints relating to refunds of overpayments were up 126 percent on December 2013.

Matt Ridout of energyhelpline.com said: “It is clear that, following price rises, high supplier profits and service issues, consumer confidence in energy suppliers has hit low ebb. Prices are at an all-time high and customer service problems seem to be deepening. It is no surprise that bill-payers will be getting frustrated and angry as many are experiencing truly awful service.”

He concluded: “We know that some suppliers have had waiting times exceeding 30 minutes on their customer service lines recently. We urge suppliers to tackle their customer service issues as this is an unacceptable situation for many of their customers.”