Moving of cruise dates

I booked a cruise to Portuguese islands in January 2021. I understood when this got cancelled and they moved my booking to 11 January from Durban to Cape Town (at additional cost). I booked flight tickets for these dates. Now they changed the date from 11 January to 9 January without informing me. The changing of flights are going to cost me an additional R2 500 and they just don't care about it.