My elderly mother has been in hospital for around 6 weeks and, last Friday, it was clear her BT Mobile service was inactive. After digging about amongst correspondence, it became clear that her existing direct debit arrangement with BT would not automatically roll-over for the new EE platform, and that she was required to settle her existing monthly charge.
Since she had not been aware of this, the cut-off date was missed and so the SIM became inactive.
The correspondence advised that the quickest way to turn the SIM back on was to pay over their website but, with the SIM being inactive, I could not link the phone to her account as any passcode which was automatically fired back wouldn't be received.
So I ended up paying two months worth of charges using my own handset and using the keys to type in the bank details. My banking app showed the payment to have gone through almost immediately but that was Monday and the SIM is still inactive.