The General Department of Taxation issued Official Letter 06 / TCT - CS on Purchase VAT when purchasing goods or services by installment payment on January 3, 2017.
The main contents are as follows.
In the case of installment payments, declaration of purchase VAT will be
accepted at the time of purchase of goods / services based on the supplier's
invoice.
Even if the company does not pay by the due date, it is not necessary to
modify the VAT declaration.
Even if you actually pay, if you do not have the certificate documents
concerning the payment of the bank, you can not declare it as a purchase
VAT.