I have an old Sony Ericsson work phone (8 years old) which has a broken scroll button, so it is of limited use. I searched through my drawers for an old Nokia mobile phone I bought from Asda about four years ago. I took the SIM card out of the Sony Ericsson and put it in the Nokia. When I entered my fou number digit (the one I used on my Sony) I got the message "SIM not valid". I can't remember any numbers that I may have used to get into the Nokia because the texting on it didn't make any sense and I'd given up on it soon after buying it. Is there a way I can get into the Nokia with my Sony SIM card inside it?
The way I read the question is that the Ericsson is the phone Explorer has been using but has now broken. So Explorer is now trying to use the sim in another phone. But I often do get the wrong end of the stick.
When I asked the man at the enquiry desk in Asda, why I couldn't use my Sony SIM card in my Nokia (Asda) mobile, he said that it is because my SIM card from work uses O2. I haven't used my Asda phone for a few years, so it is locked out of use anyway. I asked my managers at work if they could order me a new phone as it is now part of our standard issue. I've been waiting for about five weeks to get one so far.