Does it work when your outside your home?
If it does but not indoors then presumably your home is blocking the signal?
Do calls/texts work OK indoors?
Does it switch from H/H+ to 3G or something like that when indoors?
If that's the problem then you might be able to shop around for sound sort of indoor signal booster but I doubt that 48 can recommend anything and I'm not even sure if those devices are legal here?
Hope this helps.