Problem changing Annex M to Annex A

Hello friends
I have a problem. My modem is BT Home Hub 5 and I have a lot of noise in my home ADSL phone wiring. My problem is that in the settings when I want the modem to work only on Annex A, when I change the Annex type options or change the tone or offset, it does not change status from Annex M to Annex A. If I have a D-Link modem, this change of status is easy. And because I have a lot of noise, I do not have a stable internet connection in annex M mode. :frowning:
What should I do? Is there no solution? Is it not possible to solve this problem by updating to the latest version?

My Device : BT Home Hub 5A
My Current Version : 19.07.8 git 22.045

How to Disable Annex M ?

edit the file here with winscp

G.992.3 Annex M
G.992.5 Annex M
add this sign in front of #
try this