The Energy Ombudsman received a record number of complaints in the first half of 2014 – more than double the amount recorded in the second six months of 2013.
The ombudsman received a record 22,671 complaints from disgruntled consumers from January to June 2014 – a sharp increase on the 17,948 that it received for the whole of 2013.
Some 84% of the complaints related to billing as customers had inordinate bills delivered to them over the year.
June saw the most complaints in a single month with 4,124 unhappy customers taking formal issue, a 216% increase on June 2013 figures.
"The spike in complaints is in part a result of the rising cost of living, but also as a result of consumers becoming more aware of their rights – and feeling more empowered to act and fight for a fair deal," said Lewis Shand Smith, chief energy ombudsman.
"Addressing these concerns is crucial to restoring consumer confidence in the sector."
In addition to the mother lode of billing-related complaints, transfer issues made up 13% of all complaints.
The statistics come just days after the Citizens Advice released figures showing that the number of complaints during the first quarter of 2014 from customers of npower and Scottish Power doubled thanks to problematic new billing systems.
Complaints about npower rose from 306.8 for every 100,000 customers during the closing months of 2013, to 592.4 between January and March - or one complaint for every 168.8 customers.
Scottish Power received 197.7 complaints per every 100,000 customers – up from 100.5, stated Citizens Advice and Citizens Advice Scotland.