Thousands of EE customers in London lost access to 3G and 4G data services this week, as the broadband provider was hit by a network outage.
Subscribers took to Twitter to vent their frustration, as some were unable to connect to mobile broadband for up to two days, reports the Evening Standard.
The outage is embarrassing for EE given that only this week the firm boasted about the launch of 'double-speed' 4G services in the capital.
Olaf Swantee, Chief Executive at EE, claimed his company's infrastructure upgrade work was making the UK "a world leader in mobile networks" again.
However, customers affected by the outage may have settled for basic internet access this week via their dongles, tablets and smartphones.
A spokesperson for EE explained that an IT failure had caused an "intermittent issue" with the EE network, temporarily affecting some customers' data access.
He said the outage was "in no way connected to the ongoing rollout of 4G+ in central London".
"Teams worked at our switch sites to ensure the vast majority of customers were connecting successfully within a few hours," the representative added.
He apologised for the inconvenience caused to EE customers during this time.