Sputnikboy

Hello everybody,
months ago I found a cheap roundtrip Y ticket TRS-MUC-KIX, no change or refund possible. The one way flights were very good, as usual. Then while traveling (not in Japan but in French Polynesia) I got injured (ruptured Achille's tendon, surgery needed as soon as possible): I tried, with medical certificates, to ask Lufthansa (japanese call center) to anticipate my flight to no avail, my fare didn't permit that. Okay, thanks a lot Lufthansa... So I got a one way flight with Aeroflot NRT-SVO-VCE and returned home to get surgery. Since I'm honest, I tried to call the italian call center to tell them I was cancelling the rest of my flights because I'm already in Italy (and relagated home after surgery...), but the number is blocked by my mobile provider because it's one of those 899 numbers which impose ridiculous fees. Tried to contact them on twitter but it was absolutely useless, call center or nothing: unbelievable...
Once again, through another person, I used the japanese call center: they cancelled the rest of my ticket but I was also told that Lufthansa might ask me money because I did only part of my ticket and the one way cost (of course) more, so I should contact Lufthansa Italy about that. SURE! Not only I'm not gonna contact anybody, but I'm outraged that they would do something like this after leaving me high and dry in a very tough situation for me, when at the same time I lost quite few euros having to cut short my travel and book new flights. I know perfectly that a ruptured Achille's isn't life threatening or a super serious condition, yet again it's something with which you simply cannot continue to travel.
Suggestions? What are the actual policies on these matters?
Thanks everybody for the help!