Users of the mobile networking service giffgaff have reported issues with their service and claim they have been unable to receive calls.

Reports of issues began to appear on Down Detector, a website used to report online outages, at around 10am.

giffgaff is a mobile network service that operates on the O2 network.

On Down Detector, users have cited issues mainly with mobile phone usage, with others reporting no signal.

Users took to Twitter to share their issues.

One wrote: “@giffgaff are you having issues today? No incoming calls or outgoing from the network. Other networks fine?”

Another said: “Every time I make a call, the call fails. Every time! When it used to connect, I used to get spells of quietness where the call had failed… what is going on?”

Is giffgaff down?

In tweets replying to customers, giffgaff has acknowledged it is aware of an issue.

Tweets read: “Hi there Bobby. We are aware of a network issue affecting calls and we're working to resolve this as quickly as we can”

The service has provided a link to check on service updates which can be found here.

At time of writing, the service updates shows a fault with making outgoing calls and that it is being investigated.

giffgaff said: “We are still investigating the root cause. Our tech team has noticed that many members are currently reporting that this issue is mainly affecting outgoing calls. Sending/receiving texts, incoming calls and using data, do not seem to be impacted, however we will continue to monitor this closely and will keep you updated should this information change.

“We have all hands on deck and are collaborating with various teams to identify what is causing it and find a solution.

“We are very sorry for the inconvenience this issue is causing, and we hope to pinpoint the cause as soon as possible.

“We will continue to keep you updated as new information becomes available here.”