My research today shows that the scandal within a scandal here is that the regulator could not order Eon to pay a penny back to customers. The law would not allow it. The only way the £12 million "penalty" was reached was through agreement with E.ON itself.
The law has only just been changed to allow Ofgem to force energy firms to payback - and they are not allowed to use it in cases (like this) where the misdeeds go back years.
E.ON has said it will compensate customers it may have mis-sold to. Find out how to make a claim.
E.ON boss Tony Cocker has apologised after the energy firm was found to be misleading customers, according to an investigation by Ofgem.