The consumer advocacy body recognised Eon at the same time as launching its new complaints handling league table for the small business community.
The chart has ranked the 15 largest firms that provide energy to 10,000 or more small non-domestic customers on how effectively they deal with complaints.
Citizens Advice said it hopes small businesses will use this tool to make more informed decisions about who supplies their gas and electricity. It also hopes to motivate suppliers to improve customer service.
Top performer, Eon received a complaints ratio of 21.1 per 10,000 customers. SSE came second with a ratio of 29 complaints per 10,000 customers.
The supplier with the worst complaints handling is Extra Energy, with a ratio of 1225.4 complaints per 10,000 customers. Common customer issues with Extra Energy included not being billed on time and receiving large catch-up bills followed by swift action to recover debts.
“Small business owners rely on smooth running of essential services to run and grow their firms” said Citizens Advice chief Gillian Guy.
Supply issues can easily have serious knock-on effects for small businesses Guy warned, including causing financial stress. It is therefore “crucial” that suppliers are able to tackle these issues “swiftly and effectively”.
Observing the new league table business minister Margot James said: “There are more than a million businesses across Britain with fewer than ten staff making a great contribution to our growing economy. All businesses need energy and deserve to have their complaints taken seriously by suppliers if things go wrong.”
James welcomed the new Citizens Advice league table saying it “shines a light on bad practice”.