Frustrated like talking to a brick wall

I got my home loan through Nedbank, the service was incredible, must give them that. However I also did my life policy through Nedlife . In November we realised that Nedbank Home loans was deducting the bond payment and the Life cover, I then contacted Nedbank requesting them to please change this and only deduct my home loan and Nedlife to debit my personal account with the life cover premium. Nedlife immediately made the changes sent me a mail confirming this. BUT Nedbank still after contacting them took both instalments, I was then requested to go to a Nedbank branch and they will refund me the amount. I find this poor, it is a banking institute and they can EFT this to my personal account, but I went. For 2 months things went smoothly. Low and behold comes end February Nedbank home loans does this again. Nedlife already takes their instalment from my personal account, and so does Nedbank home loans so there is a double instal going off, I called them immediately requesting them to please reverse this amount, their error I was told to email a session form to Bhavika that my problem will be sorted immediately I will receive my refund. Have had NO response it is 7 days