Hi Nigel,
I'm having the exact same issue and I've no clue what's causing the problem.
My brother who is on Vodafone is the only person who is successfully able to call me. Everyone else gets the same "this number is not recognised"message. My data works fine, all outgoing calls are fine regardless of network, and texts are all working too.
I've recently ported over from another provider and kept my number, and have had this issue for the past few days only (it was working fine at first).
The same issue I'm getting taken through steps to check my phone settings etc however getting no solution.
Did the tech team explain what was causing the problem and how they resolved it?
Thanks
Robyn