Hoang Hong Hoa, an office worker in Thanh Xuan District, said since early September, she has had to block messages from 40-50 mobile phone numbers which regularly send spam to her phone.

“The messages are sent from so many subscription numbers that there is no way to deal with all of them,” she said, adding that she still has to delete dozens of spam messages every day.

Vu Hoang Nam in Cau Giay District also complained that he receives over 20 spam messages a day and several “spam calls” inviting him to buy goods and services. He once contacted the mobile network operator and asked for help to prevent spam incoming messages and calls. However, he was told to just ignore the messages and calls.

“They told me that they cannot do anything to help me, and that all subscribers of all mobile networks are suffering from the same thing,” he said.

Meanwhile, Vu Hoang Hai in Nam Tu Liem District complained about the number of spam messages from OTT apps like Viber and Beetalk.

“Though OTT apps are helpful, I still decided to remove the apps from my phone because I don’t want to be bothered with spam messages,” he said.

A senior executive of VinaPhone, one of the three biggest mobile-network operators in Vietnam, confirmed that VinaPhone has heard many complaints from customers.

To date, the mobile network operator has locked 460,000 simcards found as regular senders of spam messages.

Other mobile-network operators said they now provide a service which allows subscribers to prevent messages from selected mobile numbers.

However, they admitted that the solution cannot help much, because the senders can send messages from many different subscription numbers.

“It is nearly impossible for mobile network operators to check the content of every message. Meanwhile, the number of messages from certain subscribers is not big, therefore, the ‘filter’ on our system cannot detect whether the subscribers send normal messages or spam ones,” the senior executive explained.

The officer also said mobile network operators “cannot do anything to stop the spam messages from OTT apps”.

“In general, OTT service providers and OTT users negotiate about how they will provide and use services. Meanwhile, the only task mobile network operators have is ensuring the high quality of the transmission line,” he explained.