We are on a long line and fairly often have problems with the connection to the exchange. Recently there has been a sudden change, calls on the landline are crackly and quiet. Quiet line test you can hear feint crackling pretty much constantly. Broadband speed has dropped, and regularly "hangs", so you are waiting for ages for a page to load, then you refresh it and it loads fine. The attenuation has increased from 59 to 60dB and the noise margin is up to 9.5dB from 6dB. Phone call to EE, they do a line test and it passes the line test all ok and then they refuse to go any further. They wont investigate the broadband unless it drops below 1mbps, but its not the throughput that is a problem its the constant hanging/freezing when there is no throughput at all.
Any advice on persuading them to investigate further? Is it correct that I cannot speak to BT myself and can only go through EE?