Charge wrong premiums which don't add up

I agreed to a premium of R553.89 for my building's insurance when I purchased my home. I confirmed the premium a few times on the sales call because I could get cheaper elsewhere and they gave me a discount to beat the other company. Please refer to the sales call on 24 June 2022. This is also the premium that is shown on my policy schedule sent to me on 22 September 2022. Now, for the last two months, I've been charged R887.26! Looks like they hope you don't notice while they sneakily take your money!