Calls are currently not being connected to this number. - iPhone 5s.

I have lately realised that calls are not coming through to my iPhone 5s. When people call, it says 'Calls are currently not being connected to this number.' . I cannot even call my carrier (T-Mobile on 150) . I have called my Carrier, checked settings, restored my iPhone, however nothing has changed. How can i fix this issue? If this is a hardware issue, how much would it roughly cost (UK-Apple)? My sim is not the problem, also this phone is unlocked, and does show network bars on my T-Mobile sim, however if i switch it to a EE sim, it shows 'No service' on the icon bar.