While you cannot restore your entire wallet without your backup phrase, you may restore part of your digital assets associated with a private key.
If you have the private key of an asset, you can create a brand new wallet then use the MENU > Tools > Paper Wallet Import, and use the private key to get the balance into the new wallet.
Disclaimer: Please make sure you do not share your private keys with anyone, including the Jaxx Liberty User Success team, as if someone gains access to them, they will also be able to manage your digital assets.