Get on the phone to them,I have just been through all this with them they came out done a load of tinkering and a spot of rewiring in the box.That worked but the speed fell again so i phoned them back they came out again and swapped me over at the box round the corner beside my local shop.I have phoned them so much i am on there special case now with a really freindly chap called Tebez in India who has been really helpfull turning up my B razz i think it is called speed back up. 🙂