Hi thesoleplayer,
You've reached out to the community because you're having issues with volume automation via GarageBand on your iPhone. Is that correct? If so, we can help you figure out why that's happening. Try our recommended steps when you have a chance by clicking the link below.
Automate volume changes in GarageBand for iPhone - Apple Support
Please know that you can automate volume changes over time using automation curves. When you show track automation, each track's automation curve shows the volume level over time. You can create volume changes by adding automation points and dragging them to different values.
That said, please read through and complete the steps in the article titled "Automate volume changes in GarageBand for iPhone."
If the original problem persists after trying the steps above, please provide us with specifics on what you see for more help, and we will continue from there.
Thanks for using the Apple Support Communities.
Cheers!