B3 Funerals not sticking to the contract.

My name is Paul. About 8 months ago I took out a R50 000 funeral cover for my grandmother with B3, In November 2020 , I got an sms from their underwriter Bryte Insurance to the effect that they were parting ways with B3. In the meantime, B3 managed to get a new underwriter , however the terms and conditions of our contracts were also changed. Our initial premium of R207 for R50 000 was increased by more than 100% to R575 per month. The other option that was pushed down my throat was to decrease the cover to R30 000 for an increased premium of R375 pm.

My problem is that I did not sign for such. I signed for R50 000 at a premium of R207

How do I force B3 to stick to the original agreement?