​@Walsh1710  Hello and have you checked to see if there are any planned works  or outage in the local where you receiving difficulties? You stated the WhatsApp works fine is this on your mobile data, as WhatsApp will work if there WiFi able.

Please check network status if you've not done so already. Any problems please get back to this topic. 

Have you also tested the sim card into a different phones or location. 

Is this problem isolated to a know location but works elsewhere? 

https://www.idmobile.co.uk/help-and-advice/coverage

Joe

Hello, I am having the same issue. I have checked and no outages in area. Not an isolated location it happens in and also not the phone that's the issue. Looking back on the questions this seems to be quite common for a lot of customers. 

How do we fix this? It's very frustrating when people are trying to get hold of you but you have no idea as your not receiving calls.

I’m hoping I remember this right! 
go to setting~messages turn off iMessages 

then go to setting~general~reset iPhone 

then when it resets go back to settings~messages turn iMessages back on and re type in your phone number which was underneath the iMessage setting. 
I think that’s right, because I was in a chat with an operator and it deleted the instructions when I restarted, so that’s just from memory. 
I think it’s something to do with transferring your sim to your old number. Similar has happened to me in the past and it somehow went back to the sims original number. I hope this helps 

Sorry!! In the reset option you need to click reset network settings. So when you come back on you will also need to join your WiFi again 

Hello ​@Walsh1710 

Thanks for posting. 

Sorry to hear of the issues you have been facing with calls. 

Have you been able to check for any known issues in the area? 

Thanks, 

Natalie