Apparently this is not unique

I have no dial tone on my home phone, but my internet works. I've spent a couple of days with looking for the fault and so far no dice. Wednesday they come and check the lines in my yard. I finally thought to google "no dial tone but internet works fine" and lo, I am but one of many. Apparently one line can break and the other will carry the internet (or something like that, I choose not to understand any more than that) but both lines are needed for a phone call. Alternately, some sort of connection at the exchange may have lost contact with my phone line but still be contacting my ADSL. I'm expecting the former since a tech has already apparently looked at the outside my home things. I've tried 3 separate phones and combination of direct into the wall and in via the internet splitter - so its from the wall onward somewhere. I know theres an old line under my house that we don't use, but its split off after the main entry point (I think) so I'm hoping thats not interacting with it.