insurance *****

I purchased a house for 2,3 million, and took a bond of 600 000, now standard bank is insuring the house for R4.8 million and is debiting my account for R990 per month, i have on more than 30 occasions spoke to them to cancel this and refund me they refuse, i have had the attorneys speak to them but they refuse,i have written 30 letters of cancellation to them, i have even spoken to them in person. This is wrong.