First and best place to start is the members forum if you have not already done so but if its anything like the problem I had then you need to keep on at them.
Basically my speed was about 2.5meg, dropped to way less than half and was very erratic, constant disconnections. Some days could not access the net at all, did all the usual things (filters etc), talktalk 2nd line support and the members forum technicians all said tests show there was no problem and that I would have to put up with low speed as it was in their acceptable range, was called a liar, had the phone hung up on me several times, in the 3 months I had the problem spent 7 hours on the phone, you have to keep repeating yourself over and over as they don't read notes, make promises they don't keep, constantly told there was NO problem their end so it MUST be my pc, router, filters etc,etc, etc.
I had had enough of this crap so called to get MAC code, had a good rant and was talked into having a BT engineer out to check house phone wiring.
No problems found here, a check in the green box up the road and found loose connections, internet was better but not good enough.
A few days later had another call from a BT engineer at our exchange said he had found a problem and will get onto talktalk for permission to correct it.
Later that day talktalk called to say problem fixed, a couple of tweaks to the line profile and hay presto speed back to a constant 2.5meg....best it's ever been.
So as I say keep on at them, don't let them tell you it's your equipment at fault all the time (obvously check first), have a rant it worked for me.
I am going to complain to Charles Dunstone (chief exec) to see if I can get some compo for all the hassle I have had to endure over the last 3 months.
Good luck.
