First, please check that you are using the correct wallet and correct paper key. For users with multiple wallets, you may have different balances on different wallets.
If you are using the correct PAI Up wallet account and you know you should have a balance above 0/USD/BTC/PAI etc, you may need to re-sync your wallet.
To sync your wallet, go to Menu --> Settings --> Sync Blockchain --> Start Sync --> Sync
Please note that syncing your wallet can sometimes take several hours depending on the amount of traffic on the PAI blockchain. While you are syncing your wallet, please remain in the app and do not exit out or switch to using another app, as this will interrupt the syncing process. Don’t worry, let your wallet complete syncing and your correct PAI Coin balance should eventually display in your wallet. While you wait for your wallet to complete syncing, you can go to https://paichain.info and use your public key to track your transactions by entering it in the search bar on the page.