Q: In GarageBand for ios, I changed the key to a song, and then changed it back to the original key, but everying was an octave lower. How can I restore it to the original key?

In GarageBand for ios on my iPad, I changed the key of a song using the tools, and then changed if back, but when I changed it back everything was an octave lower that it originally was. How do I restore it to the original key?