Puzzling and frustrating interference on my MTN line

Hi All.

I am hoping someone will have an idea with regard to the problem I am having with my line.

I have been using this line for years now with no issues whatsoever until as recent as a month and a half ago. When I am at home I suffer from messages of "Network failure" when trying to make a call, people cannot even call me when at home. Now, here comes the strangest part, when I move away from home, about 250 meters away I get the phone working. I have already tested that three times to realize that the problem is around my place.

My phone works perfectly anywhere else except at home. As far as I know, nothing has changed at my place that would maybe cause this interference. I also have a Vodacom line that works with no issues at all.

Is there someone who has experienced something along these lines who can perhaps assist me?

Thanks.