Nedbank homeloans unauthorised debit order

On the 10th of June I cancelled my Nedbank home owners insurance (P***) effective 30 June 2019. I was asked to send proof of insurance which I did on the same day. On the 26th of June Nedbank again debited my account with the bond instalment as well as the full insurance premium. After spending most of the day on the phone between homeloan accounts and insurance, being told different stories, from being promised a refund to telling me a refund is impossible, I finally settled with the explanation that I was paying in arears and would therefor not be able to get a refund, but it was confirmed that my new installment would be R8207 per month. On the 10th of July I received an email that a pro rata amount of R251 was refunded to my homeloan account. I called homeloans to ask for this money to be refunded to my bank account and was told that this is impossible. I accepted it with the hope that everything will be better from the end of July. This morning my account was again debited for the full R8745. This is unacceptable and is going to result in me not being to meet my other obligations. There is also no way that I am spending half a day on the phone trying to resolve this just ending up being told I have to accept it and it will not be refunded. Nedbank is debiting my account with an unauthorised amount and I will not accept that you can not refund me this money. Please ensure that my money that you have taken *******ly is refunded to my bank account immediately or I will reverse the full debit order, since it is unauthorised. It has been two months and they cant get it right.