Downloading or replacing world on realms not working

For the past year I have been trying to put my hardcore world on to realms . I have tried replacing it and downloading it the world size is 700mb . Every single time that I attempt to download the world to realms or replace it it gives me an error and won't let me download my world or replace a current one on realms.

It seems that I am paying for realms but can't use the features that realms gives you and my money is just being wasted ! Why make a feature in the game make people pay for it and then it just doesnt work?

I just want this issue to be fixed because minecraft bedrock is so awful and I want to switch over to Java on my PC it really does suck that my only option is to use realms .