You need to provide more info.
Does anything work?
Do you mean that you get few signal bars?
Or does it lose connection altogether sometimes?
Was it always like that?
Or did it disimprove at some stage?
Where are you located?
Do you know anybody else on 48 or Three?
How do they get on?
You might want to contact 48 support to ask them about this:
http://www.48months.ie/help#ask-a-48-agentHope this helps.