Mobile network O2 has suffered a network outage, in which thousands of customers were left unable to make calls, send text messages or use data for several hours.
O2 claims that only one per cent - or about 229,000 - of its customers were affected by the issues.
The outage, which occurred yesterday, affected customers in many different locations across the UK, including Birmingham, London and Manchester.
The mobile operator updated customers on the outage on its service page yesterday morning at 10:45am, stating that some customers may have been experiencing difficulties using their mobile phone, but that they were "working to fix the problem".
The service page was then updated, with O2 claiming that the service was "improving" for customers who may have been impacted with issues in using their mobile phones.
Many of O2's customers took to social media network Twitter to vent their frustration at the mobile giant.
With user @LucyBeck2011 tweeting "Moving networks ASAP. Absolute joke!".
Telefonica-owned O2 claims that the issue was fixed yesterday at 11:45pm, and only affected a small proportion of its customer base.
"The intermittent problems experienced by some of our customers today have now been resolved. Routine upgrade work on our 2G and 3G network led to unexpected congestion affected around one per cent of O2 customers," it said.
But customers have now flocked to Twitter to ask for compensation from O2.
User @Widerife81 tweeted to O2: "What compensation are you offering for the 3G outage yesterday?".
This isn't the first time O2 has had issues with its network. In July 2012, the network's phone and data network services suffered outages over a 24 hour period.