You can't see your balance on the ZERO as it is completely offline. This is for practical and security reasons.
Your balance would need to be retrieved online from the blockchain and would need to be updated frequently. This requires 2-way communication between ZERO & LIQUID. Synchronization is only possible from ZERO to LIQUID, not the other way around. For security reasons we limit any incoming communication on ZERO to the data that is necessary to sign a transaction.
You can see an up-to-date overview of all your funds on the LIQUID app in all safety. Your private key never leaves your ZERO.