This State Bank of Vietnam (SBV) and the Central Bank of Vietnam have declared illegality as legal means of payment to the bank after refusing to include these cryptocurrency among non-cash payment methods approved by these officials. They stop issuing and use bitcoins as legal tender in the country, and Vietnam's central bank has enacted the law.
According to the report by CCN in October, this is seen as a result of bitcoin originally as an illegal payment instrument. In this bank card (credit and debit) as non-cash payment, cryptocurrency are not included. It has recently updated the legal framework for payment instruments which are checking them for payment orders.
SOURCE - https://www.ccn.com/vietnam-bitcoin-adopters-face-criminal-prosecution-fines-9000/