"Stuff up" with prepaid / normal electricity account

My 73 year old mother had prepaid installed on 6.1.2017 and todate has been trying to get the account sorted out as she is still being billed for normal electricity. My mom has spent hours on the phone and has an arms list of referenece numbers. Even having gone into the Head Office in Braamfontein and Booysens on numerous occations - no one is able or willing to sort out the mix up caused by City of Power's poor administration work flows. No one will take responsibility and assist.