The government has given no indication as to when the ban on the applications will be lifted.
International Internet Gateway (IIG) operator Fibre at Home's Strategy Officer Sumon Ahmed Sabir said about 10 GBPS of their data had been used daily on an average to browse Facebook and for other apps before the ban.
"But the usage has slumped by 30 per cent since last week," sabir was quoted as saying by the bdnews24.
The ban has cut through the average data usage on mobile phone by about 30 per cent.
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An official with a top mobile-phone operator said their internet package sale had also declined.
Another official feared a lengthy ban would discourage mobile internet use.
IT expert Mostofa Zabbar criticised the ban, saying it was having "a negative impact and harming the business".
Bangladesh government blocked Facebook and online messaging and calling services like WhatsApp and Viber on security grounds last week over security reasons.
The order came immediately after the Supreme Court upheld death penalty to war criminals Salauddin Quader Chowdhury and Ali Ahsan Mohammad Mujahid.
Prime Minister Sheikh Hasina said on November 11 that the government was contemplating to block Viber and WhatsApp Messenger temporarily in the country to track down the cyber criminals.
Bangladesh executed Jamaat Secretary-General Ali Ahsan Mohammad Mujahid and BNP leader Salahuddin Quader Chowdhury for war crimes during the 1971 war of independence against Pakistan on Sunday, triggering sporadic violence by their supporters and the fundamentalist Jamaat-e-Islami calling for a nationwide strike.