Fibre connection dropping

[#1]

My Fibre connection has dropped twice today with the Concentrator not reachable error
I still have DSL sync showing on the BT Modem but the router will not connect
On both occasions leaving the BT modem powered off for about 20 mins allows the connection again
On the 2nd occasion after doing a speedtest my upload speed has dropped to less than 1mb (usually about 16mb)
<a href="http://www.speedtest.net/my-result/4282456233"><img src="http://www.speedtest.net/result/4282456233.png" /></a>
Anyone know why this keeps happening ?

[#2]

same here , happened this morning for about 2 hours , disconnected about 25 times during those 2 hours , speed dropped under 5Mb ( from 70+) ... tonight here we go again , having micro disconnection , every time for a few seconds then come back... contacted support on-line chat , no issue to report all they could say was > report a fault ... i don't need to report a fault that will take days to be diagnosed and most probably would be fixed when they check it , i need it checked up right now when the fault is happening....