The FACEPLATE on the Master Socket (The part in front of the master test socket that you plug the phone in) isn't considered part of the Master Socket. If the phone works in the master test socket but not in the faceplate, it could be a lot cheaper in getting an outside and approved contractor or telephone engineer to fix a new face plate than getting Open Reach to come out and fix a new faceplate on the socket.
'Well, I don't feel it's right paying for a charge to Open Reach to fix my fault...'
The first thing you should do is call your telephone provider. The telephone provider should be able to get the engineering notes on the case from Open Reach. The engineering notes will explain why a charge was applied.
Some charges have been reversed in cases where the engineering notes do not match the case in hand and a credit from Open Reach is raised on these issues. Sometimes, they do take a long time to resolve, especially when we have to appeal to Open Reach about issues and/or the network provider.
However, these are a minority - most charges are related to situations outside the remit of Open Reach. If, after checking the phone line with your telephone provider, reveals no faults detected on the UK telephone network, try doing some of the checks listed earlier.
If the fault is related to the phone, replace the phone or don't use it!
If it's equipment that is using the phone line, look into getting the equipment replaced or removed from your phone line!
If the fault was internal wiring within your house, such as the faceplate (see above), independent telephone engineers or contractors can do it within your house at a fraction of the cost.