All the files in my account disappeared after upgrating the plan

Hi there, 

Welcome to the Box Community, I'm happy to help!

Files/folders may not be accessible as your account is being transitioned to the new plan. This process can take up to a day to complete and once the upgrade is completed, your files/folders should be accessible to you again. 

Thanks for your participation in the forum and please let me know if you have questions.

All the Best,