BT Broadband

I am trying to arrange a second ADSL line for a local company that I offer IT support to. The reason for a second ADSL line, is that the first ADSL line seems a little intermittant, and as this company uses the internet for the core of its business, then it really has to be up 100% of the time.
The intermittancy is sometimes cured by rebooting the modem, ( a WAG54G ), swapping to a backup modem containing the same configuration, replacing the PSU ( we have now lost 3 PSUs ) or waiting for BT to 'test' the line, when they find no fault, but the modem magically starts to see ADSL carrier again.
So, I ask BT for a second ADSL line on a 90 day trial, just to try and see if it is more reliable. I wait for two weeks and no carrier appears on the second line, so I phone BT Business and they can find no trace of the order. I re-order the line and this time receive a notification to say that I have been given 'IT support manager' for 3 PCs. After being passed around BT for 40 minutes, I find that BT Business are on commission, and they have a track record of 'adding' features when offering broadband. I have to escalate the call to be able remove this feature from the order.
I will hopefully find out if the second line works, and if it is more reliable than the first ADSL line.