Uni 27-10-2016 - Guidance on VAT refund for contract late payment

According to official letter 4138/TCT-CS:

In case, Late payment for the exported goods, services must be stated in the contract. If there are not bank notes due to not until payment time as contract, the business establishments still is allowed to declare, deduct input VAT. Until the contract deadline, business establishments must present bank notes.

When payment incurred, business establishments do not have bank notes, they must declare, reduce input VAT for non-payment goods, services by bank transfer in the tax period paid in cash (including that tax authority and other agencies issued inspection decision in that tax period incurred the deducted, declared VAT amounts).