I can't upload my world to my realm

I've created three realms to try to play my ore-existing world on today. Every time I chose "play on realms" it bills me $8.63, then sends me to my real and to a random world that's not even the one I have been playing on. When I go to replace the random world with my own called "Cobracraft 2021," it gives me an error message and I'm unable to make it my world on my realm. I would like a refund for the two realms I don't need that I closed, and the ability to play with my world on the one realm I have open.