SSE has paid out £190,000 in compensation to customers after it withdrew from a partnership with social enterprise Ebico, and failed to quickly move customers onto another tariff.
Suppliers have 49 days to move customers onto a new tariff if the one they are on is withdrawn, but SSE failed to comply with its licence by taking almost six months to switch customers over.
On Thursday, SSE said it had compensated all the customers affected and had a customer support team for those who needed further help.