It seems even more difficult to talk to someone re problems with a phone line, when you do eventually get through the maze of options, make sure you remember them all or you could find yourself down the wrong rabbit hole. However, once successfully through to a person, it seems that the problem is for you to fix by doing all sorts of technical things - why do I pay so much money to BT every month, it's certainly not for the quick and effective service. Since agreeing to send an engineer I have bent sent repeated texts suggesting that I fix the fault
They are asking you to do some checks to ensure that the problem is not on your side of the Master socket. If it is on your side , extensions, filters, handset etc the you would be liable for a hefty charge. Then you would start complaining about it.