In a statement on its website, it said customers in some areas nationwide may find data services affected because of a technical issue.

“Our technical team is working hard to resolve the issue and restore services as soon as possible. Affected customers are advised to restart their devices,” it said.

A number of customers took to Twitter to vent on their inability to surf the web.

Ehsal Jesrin said: “Come on Celcom, (I) paid hundreds of ringgit and (now am) having this problem!”

Another user, Cik Siti, tagged Celcom and said: “On the busiest day ever! I have classes! From 8am to 9pm, and this is the day you choose to be like this.”

Some users asked to be given free internet once the issue was fixed.

Last month, Celcom provided its users with six hours of free internet following a three-hour breakdown of services.