Energy watchdog Ofgem has slapped Green Star Energy with an order to pay £350,000 as tenants were paying higher fees.
Ofgem said that 1,829 tenants were unable to access their accounts and were unable to receive cheaper tariffs.
Despite being made aware of their failings Green Star failed to adequately address these issues or inform Ofgem.
Green Star will have to pay each affected customer £60 which totals to £109,740 in compensation and the firm will also make a voluntary contribution of £240,260 to the energy address fund.
Since the probe by Ofgem Green Star has now updated their accounts and systems.