It seems like you're on one of our older SIM cards, we are phasing these SIM's out as they will not work by the end of the year. This wouldn't be down to the reason you're having issues, but getting you one of our newer SIM's could help resolve this problem. If you're happy for me to do so, I will send you a private message and get this done for you?
Right thank you for confirming all of that for me 🙂
What happens next is a SIM has been sent out to you, it can take around 3-5 working days to get to you. All you would need to do with the SIM once you have it is activate it, on the packaging the SIM comes with, it advises you on how to do this. This should hopefully fix the issue, please let me know the outcome of what happens 🙂