Ofgem has banned Economy Energy from taking on new customers until it resolves customer service issues.
The provisional order against the supplier also bans it from requesting one-off payments and increasing direct debits.
The ban will initially remain in place for up to three months to allow Economy Energy to take steps to:
If Economy Energy fails to make improvements within three months, Ofgem can confirm the provisional order to extend the ban.
Ultimately, if the supplier fails to improve Ofgem can take steps to revoke its licence.
Ofgem has taken action due to the decline in the standards of Economy Energy’s customer service, complaints handling processes and standards, and billing and payment procedures.
Anthony Pygram, director of conduct and enforcement, said: “Ofgem is taking action to protect customers from suffering more harm from the unacceptable level of customer service provided by Economy Energy. We expect the supplier to take immediate action to rectify its failings or face having its ban extended.
“All suppliers are required to treat their customers fairly. Where they do not, Ofgem will take the necessary steps to ensure suppliers change their behaviour and to prevent further harm to customers.”