Are you absolutely sure that your settings have not changed and are still correct?
Can you check them against these and maybe post screenshots?
http://community.48months.ie/t5/Need-Help/Internet/m-p/34493#M12560Do you definitely have an active membership?
Have you tried switching off and on again?
If you manually search for networks can you see and connect to 48 3G?
If you still have problems then you might want to contact 48 support for more assistance.
http://www.48months.ie/help#ask-a-48-agentHope this helps.