so i tried the test socket and the errors have dropped massively
its lucky i didn't ring a engineer
connection speed far better in test socket so you have a problem with your internal wiring. however your stats show large numbers of crc/hec errors and error seconds for only 2hrs connected suggesting there is still a line noise problem
did you try quiet line test from test socket?
then you need to report a phone fault not broadband and once that's fixed broadband will improve