Why is a Viettel SIM in Ho Chi Minh City blocking SMS or calls, or asking for document verification, and what should you check?

Another verification route was described in July 2026: during registration you can call the number shown in the process, the code is read out over the phone, and 10,000 VND is deducted from your balance. The participant held the phone up to a translator app to note the code. In September another participant added that the first code comes by SMS and a repeat code can be requested via WhatsApp.

In July 2026 a traveler renewed a Viettel package for 540,000 VND with 6 GB per day and, in her words, checked several times that it included calls and SMS — staff confirmed it each time. A day later an SMS failed with an 'insufficient balance' message, even though she had only used data. On a previous visit another Viettel store had given her a receipt with the plan name, but this time she got none, which made it hard to check what the package included. The practical takeaway is to ask for a receipt with the exact plan name.

In July–August 2026 travelers had problems registering for Zalo by SMS: the code did not arrive on a local SIM, or the app did not detect the SMS they had sent. In August a participant replied that you should register only with a Vietnamese number issued to your own passport, since other numbers are quite likely to have been used before. He also noted that the SMS with the code can land in the spam folder.

In July 2026 a traveler kept receiving texts on her Viettel number asking her to verify it with documents. She went to a Viettel store twice — once specifically with her passport, and again to top up and show staff the texts — but the messages kept coming. Then a notice arrived saying outgoing calls and SMS were restricted because the documents were not verified, although the SIM itself kept working.

The same case shows that topping up alone does not stop the warnings: after a visit to add credit, the document texts kept arriving. In September 2026 another participant advised topping up from time to time and sending an SMS once a month, but warned that the operator can call you into the office for re-verification at any moment.