Iphone 5s ignoring some inbound calls 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?
You need to backup your phone, reinstall the operating system and then recover the data back.

This should resolve the issue, however if not, then you may need to setup as a new iPhone.

Here are the instructions on Apple's website