I booked a return ticket from Düsseldorf to Tokyo via Rome with Alitalia last month. Two days before my return trip from Tokyo I got an email saying the Rome-Düsseldorf flight was cancelled without any explanation. I called their help line and was told that there would be a strike on the day of the last flight, hence the cancellation. She said she could book another flight for me on the day after. I took that option immediately since an extra day in Rome is even better. I also asked about hotel fee compensation and she said I had to email their customer service team, which I did and still got no replies.
Later I figured on the Alitalia website that in such a circumstance I can also ask for a refund. My question is, in this hypothetical circumstance, would the refund be for the full ticket of 4 legs, 3 of which I completed, or would it be a calculated refund for the last flight that was cancelled? Has anyone been in a similar situation?
EDIT #1: I'm not asking for a refund. I'm asking for the hypothetical "what if" question. What if I hadn't accepted the rebooking how would they calculate the refund. Just for my curiosity.