Where can I top up a Vitel SIM card?
It is most convenient in their offices, you can change the tariff immediately if the previous one did not quite fit.
In grocery stores at the checkout, it is also possible. In Winmart, there is definitely their own interface, they top up through the cashier, not the seller translating it themselves.
In others, it seems to be the same system.
Otherwise, the scheme with the Vietnamese is always effective :)
The most effective scheme is to open an account and top it up for yourself) I somehow tried several times through the cashier at first, but they were too lazy and pretended not to understand me) although I showed them everything without words, clearly indicating what I needed)