Was your mobile data ever working?
If not then you probably need to configure your APN settings.
Text "APN" to 50048 and follow the instructions here to configure the APN settings:
If that's not the problem then...
What does your My48 account Dashboard say about your current membership status, allowance balances and expiry date?
What does your Transactions page say about recent payments/purchases?
Does your Buy Plan page list any upcoming membership plans?
Could it be that you have used up your current membership plan data allowance and you need to buy a data add-on rather than a new membership plan in order to continue using mobile data for the remainder of the current membership plan month?
In such circumstances buying a new membership plan won't help as the current membership plan cannot be terminated early and the new one started immediately.
Plans bought in such circumstances will stack on your account to kick in when the current one expires.
If you need to contact 48 support about this then see the links in my signature below.
