My Minecraft World's are being deleted

When I would load up my minecraft on my phone it asked me to sign into my Microsoft  account. So I tried to sign in and and it wouldn't let me. I ended up having to delete the app and I lost all of my worlds. Which was annoying but now (I thought) I could play minecraft. Until today I opened minecraft and it asked me to sign in my Microsoft account. So I did and surprisingly it let me sign in. I went to my worlds and they were all gone again. 

It would be greatly appreciated if y'all could fix this issue.

~Thank you,
Grace