I have asked a moderator to provide assistance, they will post an invite on this thread.
They are the only BT employees on this forum, and are based in the UK.
out of curiosity did you check that there is no waiting list on your cabinet as that would cause a problem on switch of ISP https://www.btwholesale.com/includes/adsl/main.html
I am so sorry to hear about the problems you've had when trying to get your services moved over. We will do our best to help you. To get in touch with us, click on my user name and then copy and paste the link under "Moderation Team Email Address" into your browser. Complete that form and we'll get back in touch with you.