I've read through a few pages of this thread, but from looking at your account it doesn't seem like either a phone or broadband fault has been reported to us?
If you've been through the normal troubleshooting then I'd suggest getting this raised to us to look into
https://faults.plus.netAttenuation: 29
SNR 9.1
Sync 14363
Indicative Line Quality: A
Mean Time Between Errors Downstream (Seconds): 163
Mean Time Between Retrains (Seconds): 86400
Former Plusnet Staff member. Posts after 31st Jan 2020 are not on behalf of Plusnet.