Broadband disconnects when the phone is picked up.
This has been an issue on and off for around a year now, and seems to clear itself up for periods before flaring up again. Recently it's been chronic, and even worse when the broadband reconnects the speed is pathetic until I restart the Homehub, and even then doesn't always help.
We got an engineer out (under threat of being charged £100 if it was our fault) and he did all sorts of line tests and found nothing. All my wiring between the hub, phone, and wall is fine, yet the issue persists.
I've no idea what to do, and I don't want to phone up BT customer services because I feel like they'll just go through the same useless rigmarole that ended with the engineer coming round and finding nothing.
Can anyone give any kind of advice on this?
Things I've tried:
A different homehub
Four different filters
Disconnecting the phone and using one connected to the hub as a landline instead