I would wait until they contact you on Wednesday, they "might" have some good news.
If not, I would tell them politely (don't be rude to them
) that you are not happy on how this is being dealt with and that you will be sending the CEO and Chairman's Office at BT to do with this on going issue.
They might give you another date that they will contact you with an update, I would tell them "Ok, I will wait until then, but if it isn't resolved by then I WILL notify the CEO and Chairman's Office by email" this may or not get things rolling.
The key factor is be firm, but at the same time don't be rude to them, especially when you send the email.
In the email just say the exact issue(s) along with your address and phone number, don't go on and on you can explain more in detail when they phone you up.
Once the email has been sent, give them up to 7 to 10 working days to respond, but in nearly all my dealing with them they have phoned back within the next day or two.
I also have their actual Switchboard number which is an 0207 number, but I think the email might be the best bet.
Hope that helps.