A new infinite world cut into my flat world

Minecraft pocket edition for the Kindle, I have a flat world that I have been building on for over a year and recently downloaded the city texture pack now I have a infinite world that is raised about 80-100 blocks high that has appeared in my flat world in all the areas that have not been built on. The new world is cut in half so oceans are cut down the middle and I can not get rid of it