Not receiving or able to call

[LHawkins]

I have spent the day unable to make or receive calls even when contacted to wi-Fi so I have checked my phone it’s not the problem which has been confirmed by a worried WhatsApp call from elderly parents with the same issues. 
please could someone explain the problem and how long it will take to fix. 

[rafi]

Even I have the issue in E12, London past few hours as Whatsapp calls and data is fine 

[LHawkins]

I Also thought it very strange that yesterday in the middle of London I had no signal.