You've been pretty imprecise in your rant - what is the extra £100+ for? By the way, leaving the cap lock on often makes people ignore your post - it's bad on the eyes, and a bit childish!
Do you really think that posting with the "cap lock" on helps you? All it does is make your post difficult to read, and others to dismiss your "rantings"!
ON the contrary, it IS childish. The person is supposedly an adult asking (?) for assistance - all he's done is the keyboard equivalent of shouting: that will get no helpful response from normal people - however valid his question might be.
I had Infinity installed and needed an engineer to come out twice but I didn't need to pay anything extra. Like you there was a problem my line was faulty not for using the phone but it wouldn't connect to the internet or if it did it kept dropping out, but the engineer came out and just installed a new line with no fee what so ever. I would get back on to BT and ask why you were charged and what you were charged for. Something definitely isn't right!
Ignore web chat. It's a complete waste of time. Untrained staff, long pauses, incorrect and/or conflicting and/or unreliable information. Not helped by the fact that it's manned by staff for whom English isn't their native tongue.
It's a joke.