ENERGY supplier Eon will pay a record £12m to vulnerable customers after breaking sales rules.
Regulator Ofgem said the redress package reflects the harm caused by Eon's poor sales practices between June 2010 and December 2013.
Ofgem said the firm failed to properly train and monitor its staff and those it employed through third party telesales agencies, leading to incorrect information being provided to customers on the doorstep and over the phone.
As part of the package, Eon will pay about £35 to 333,000 customers who normally receive the Warm Home Discount.
It will also make automatic payments to vulnerable customers affected by poor sales practices.
The company write to 465,000 customers to see if they are entitled to compensation.
Tony Cocker, Eon's chief executive, said has now ended face-to-face sales and cold calling.
He added: "It is completely unacceptable that we may have been unclear with customers about their tariff choices and as a result those customers may not have made the best choices for them.
"There was no organised attempt to mislead, and Ofgem has acknowledged this, but that does not excuse the fact we did not have in place enough rules, checks and oversight."
Since 2010, Ofgem has imposed £100m in fines and redress on energy companies for various rule breaches.