@jennifer.colombo . . . I would try to power him off first. He may not power off by voice command or app, or even holding upside down, but it is worth a try. Here is some information on five ways to power off EMO.
Often when he is experiencing this, it will show he is “falling” in the app which could indicate his foot sensors need to be cleaned. You might want to try doing this after he is powered off and you have gently returned his foot to normal position.
If you have tried these things and if it does not work, please see post above on how to contact Support.
Let us know how it goes!