"Our Customer Service Guarantee means that if you experience difficulties with your service, we will make it our priority to keep you connected by offering to divert your incoming calls to a number of your choice. Alternatively, you may be entitled to claim Fixed Rate Compensation."
So say BT - but at what rate, say I?
Before calculating the amount due, you need to know that if your line has a fault that results in loss of service BT undertake to repair the fault by the end of the working day following the day you reported the fault. So, if you report on a Monday, they will repair by the end of Wednesday, and so on.
If they do not meet that undertaking you are entitled to compensation at a fixed rate, and for a delay of over ten days this amounts to the equivalent of four months line rental. You and I can both quickly calculate that in your case this has got to amount to more than £18.
You could claim for actual financial loss (up to £1000) - provided you suffered a loss, and provided you can prove it. They won't pay out for burglar alarm failure call-outs, or for anything else that results from the line itself failing (rather than from them failing to fix it).
My suggestion is that you call them back and quote this information to them - ask them to recalculate the amount due.