My phone is now working again. They managed to sort it out when I returned to online chat the next day. I was told it was "an issue on the network", whatever that means?
It's a shame they couldn't deal with it there and then when it was first reported by my family member on their mobile. Do you know why that is? I was told that they were actually quite unhelpful.
I have another long-running saga that I will send you a PM about when I get the time, over the weekend hopefully. I've been going round in circles with customer services - phone/online chat and it's been very frustrating, to say the least.