Illegitimate double insurance and NO FEEDBACK 6 MONTHS

We have recently financed our property bond with Standard Bank. We were given the option by Standard Bank to either make use of their insurance or make use of our own. We opted to make use of our own insurance as Standard Bank was 3 times more expensive. Before approving the bond Standard Bank requested the proof of our own insurance (which according to Standard Bank we had to start paying even though the property was not even registered ). Our insurance was then approved and bond was granted. We have been paying our personal insurance AND Standard Bank insurance ever since the bond was approved. We have contacted them NUMEROUS times with no feedback, only that they would get back to us. They are aware that we are double insured (as far as I know this is not allowed) but they do absolutely nothing about it. Except from the bond we are paying thousands of rands extra per month that was not agreed upon. Next step if not given back my money or answers is a lawyer.

How could a well established bank in South Africa be so *********** and ********?