I'd like to take this opportunity to welcome you to the forums and say that I'm really sorry to hear that you've been experiencing some issues with your phone line. I guess the noise you hear must be really irritating so I'd like to help get this sorted.
I've done some testing on the line, and can see no reason why it should be behaving in this way, there are no area issues, and the line is not reporting any abnormalities.
I'd now have to ask if you've been able to eliminate the phone at all, either by trying another phone on the line, or by trying your phone plugged into a known working line. I ask this as the next step would be to book a technician to call out and investigate further.
I've sent you a private message in order to get things moving with this, please look to the top right of this page where you'll see a purple envelope icon, click on this and you'll see my message.