Sorry about that, I'm from Vietnam.
As I look at wiki via your link, I've found that Bitcoin payment in Vietnam haven't been banned yet. But there is an announcement for 2018 said that will.
exactly, the wiki may not be updated or it may even be wrong about some things.
also when the government talks about bans, they rarely are talking about banning bitcoin. i suggest paying more attention to the details of the news to figure out what is it exactly they are banning.
for example in many countries they have so far banned ICOs and investing in them. they have also banned a couple of exchanges in different countries, and closed some shady bitcoin businesses. some of them have also banned banks and big financial firms from investing in bitcoin.
* none of these meant banning bitcoin itself. *