Energy regulator Ofgem said it found ScottishPower did not have in place "appropriate management arrangements" to adequately train and monitor their doorstep and telesales agents, resulted in customers being given "misleading information".
"ScottishPower has accepted these failings, which have now all been rectified," Ofgem said.
The regulator continued: "The size of the payment reflects the impact of the sales practices on consumers and it also recognises ScottishPower’s cooperative engagement with Ofgem to put right their processes.
"Our investigation found no evidence of a strategy by ScottishPower to deliberately missell to customers."
More top news
Figures from the latest ComRes poll shows 58 percent believe David Cameron will not get a good deal for Britain.
Lottie and her dog Marley confronted a man who had taken a laptop and goods from a Lush store in Oxford.
Feeling colder with a biting, bitter windchill