We're currently aware of a problem with some calls to numbers on our network, our team are currently investigating and we will update you shortly.
UPDATE 16:55
We have isolated the fault with our carrier and are now working on a resolution. We hope to be able to send a positive update very shortly.
UPDATE 17:25
We're still working on a resolution. Please continue to bear with us.
UPDATE 17:45
This issue has now been resolved. We're very sorry for any inconvenience caused.