Was this working before or have you just joined 48?
What does your My48 account say about your current membership status and allowance balances?
Can you receive calls/texts?
Can you send any texts or make any calls?
Hope this helps.
Please clarify what it says about your current membership status and expiry date and your allowance balances.
What do you mean it doesn't connect to 48?
When you manually scan for networks do you see 48 and can you connect to it?
If you don't see 48 then try Three/O2.
You haven't clarified if you are new to 48 and this is your first time trying to use the network and membership or if it worked before now.
Hope this helps