Very slow broadband - can't identify problem

Question

Hi all,
My home broadband is running very slow, it is a BT line running into the house, a microfilter plugged into the box with the only corded telephone in the house and a belkin router plugged into it.
The phone is also a bit crackly and sometimes disconnects the internet if picked up, so by looking at threads on here, I removed the bottom half of the box on the wall and tried plugging the phone directly into the test socket, and it worked great with no crackle. But when I plug the microfilter back into the main box sometimes the router takes about 5 attempts of re-wiring everything before it connects. I looked at the 4 gold pins inside the bix that screws off the box and one is very corroded, and has pretty much snapped off. So then I plugged the microfilter directly into the test socket and it connects first time, but is very slow.
So basically, sometimes the internet works when connected to main box, but mostly doesnt connect - so does this indicate a problem with the bit that screws off. And even though the Internet connects first time when plugged into the test socket, it is still giving me slow speeds. (0.37 Mb/s download and 0.36 Mb/s upload).
I hope that is explained well enough, I can expand on any points if required.
Many Thanks!

Answer 1

try advice here
http://community.bt.com/t5/BB-in-Home/Poor-Broadband-speed/m-p/14217#M8397
and to test line for noise do this
dial 17070 option 2 and listen - should hear nothing
best done with old type analogue phone digital will do but may have slight hiss
do not use home hub phone
If any post helps tick the star box on the left
Just cause Im paranoid dont mean they are not out to get me