Premium increased with a R400.00

I am very confuse to why discovery have increased their premium without notifying clients so that we can budget or change our insurance to a company that will offer us a better deal as I am spammed on a daily basis by King Price, Outsurance etc you fully aware of who your competitors are. This is the 2nd month you debited R2900.00 out of the account from R2300.00. How does your insurance increase with a R400.00 for an asset that depreciate. Hope this matter can be sorted out swiftly. I refuse to pay additional insurance for your other clients.