Discovery Life
Premiums to stay the same on anniversary

I am very unhappy with Discovery Life and is considering cancelling my policies that I have with them.
On 1 December the premiums will go up coz its the anniversary. I phoned today telling them I cannot afford the increase and it had to stay the same. They told me I can phone on 1 Dec. and then they will make changes and refund me which will take up to 15 days. With this changes my policies will have to change to something else with lesser value.
Why can't it stay the same value and same premiums?
Not acceptable.