I have an Iphone 5s that appears to randomly ignore calls from certain numbers.
Other numbers appear to be able to connect, but most just ring out as if I just left the phone untouched.
If they leave a voicemail it pings immediately.
This is on O2 in the UK (I called their tech support and they say that it is a problem with the phone).
Any idea of what could be done to fix this? Do I need a new handset?