Atrotious connection speed, disconnections, crackl...

Question

ok i will keep it short. We have had BT for around one month in which time they installed a new external cable and new internal box into the house. It has worked fine, we have had fairly good speeds, until a couple of days ago.
First the router kept disconnecting (glowing orange light every 20 or so minutes)
then the speed just dropped out of the sky. Looking at speedtest.net we get a download speed of just 10 kbs.
the phone is also crackling so bad we cant even hear people on the line.
the bt speedtest yields these results:
 Download speedachieved during the test was - 47 Kbps
 For your connection, the acceptable range of speedsis 50-250 Kbps.
 Additional Information:
 Your DSL Connection Rate :2191 Kbps(DOWN-STREAM), 967 Kbps(UP-STREAM)
 IP Profile for your line is - 135 Kbps
The throughput of Best Efforts (BE) classes achieved during the test is - 8.51:19.15:72.34 (SBE:NBEBE)
they are sending an engineer around next week but according to the unhelpful guy on the phone there isn't a problem and the line is fine. I envisage a horrible, long saga of typical BT incompetence so i am asking if anyone can think of what could be causing it. We are on the unlimited plan, i have tried changing cables, plugging directly into the other connection, resetting the router, connecting through ethernet.
It has literally gone from being a fairly good connection ~(speeds above 2mbs) to a broken mess.

Answer 1

if its a voice line fault (the noise on it) ring the phone help desk and get them to fix it just dotn mention the bb or ther'll pass you to the wrong department and nothing will get done.
once the line problem is fixed it will either take a week to get back to normal operation or will need intervention to help it, after 3 days if there were no improvemetns it would be time to ask for the intervention.
and to confirm if its the line you will be asked to perform a bunch of test's, a corded phone plugged into the master socket (or main socket for the adsl/phone main plate) with nothing else connected and perform the quiet line test dial 17070 option 2
try it with a second known good corded phone or if possible take your phone ot a neighbours and do the test just to prove your phone is good (do the test with theres then yours and iof the results are the same your phone is ok unless ther having problems)
then escalate the problem to an engineer visit, if the problem disapears on the known good phone test its soemthing in your house causing it (either a device or a wiring problem) so you would pay for hte call out in this case, which is why i say check it twice just to be sure of the facts and save yourselff the expense, if you use a cordless phone thats over 12 months old theres every chance it could of gone faulty (the noise on the ,line) and be the siole couase of hte problem, a good replacement can cost from £20 wheras the engineer cost is over £120 but its your money and your call.