I assume we're talking Livebox here. And I also assume that your relative has gone through the motions of switching it off for ten minutes, switching back on and waiting until all lights have stopped flashing, and then confirming that the normal three lights are constant. If this is what happens then it's connecting ok and it may be time to start looking at the phone line, the phone point itself (I've had problems with these) and also the filter (try changing it).
With Orange help it can be hit and miss. I had a problem some months back I was advised all sorts of rubbish by various "helpers" until one day I was explaining things to someone who immediately new what it was and solved things there and then. I would suggest one more call and ask them to test the line if things don't improve.