I was recently sent a new SIM as Virgin said it had been "fine-tuning its network".
I put the new SIM in my phone and tried to follow the instructions that came with it, but I was not prompted to enter any code, or in fact do anything.
My phone can now no longer make calls. It can receive them, but not make them.
I have had this problem twice before - the last time it lasted for months - so I'm very keen to nip this in the bud this time.
What can be done to put it right?