Unexpected and unexplained increase

I have received an SMS saying

1. The premium for this policy will be increasing from R 170 to R 200 (18%) 2. No increase in the sum assured 3. The increase is earlier then the date agree to on the contract

The call centre agent was not able to advise why there is no increase in the assured sum and why did the premium that was guaranteed for 12 months only lasted 8 months.

Apparently (according to the call centre agent) the reason for this mid period increase is that there has been a large number of claims . This is not acceptable, the premium doesn't come down when there are low claim periods. She further advised that the usual annual increase will come as per contract date. Two increases in 1 year???

I sent an email on the 24th of November to ********** (as per the call centre agent), no reply to date!