A spokeswoman for gas and electricity providers dismissed suggestions the sharp rise in complaints was a sign of a poor energy service.
Energy companies resolve most complaints "within a few working days", the spokeswoman for Energy UK said:
If a customer has any concerns relating to their bills, they should contact their provider as soon as they can, and if possible have an up-to-date meter reading to hand which will ensure their bill is as accurate as possible.
Energy companies work very hard to resolve problems and most complaints are fixed within a few working days with no more than a phone call.
More top news
Virgin's services will only be classed as on time if they reach their destination within less than a minute of the scheduled arrival time.
Banks and building societies should improve efforts to support age-friendly banking, according to a report from Age UK.