For a while now I’ve been experiencing problems making and receiving  calls. This has got much worse recently. Sometimes if I restart my phone I can make one or two calls, but then it reverts back. The majority of the time, when someone calls me, they are sent straight to voicemail. I will usually get a text to say that I have a missed call but my phone definitely hadn’t rung. This has been happening intermittently for a few months but now is nearly all the time. Sometimes restarting helps but not always 

any help would be much appreciated