Broadband Probs'

[strugglin']

We recently experienced a lot of Internet disconnects from our wired Broadband. Especially when the phone would ring. I have got BT to check the phone line, and they say it is ok.
I have replaced all the microfilters around the house. This appeared to work initially but a couple of days later the disconnections are back. We also experience lots of phone crackling too, hence the filters were thought to be iffy, but not new ones!! But occasionally the phones are quiet and all is well.
Any help would be appreciated thanks in advance.

[strugglin']

Thanks, will look in to this as soon as possible.