I am a regular Star Alliance traveller, however due to my itinerary and schedule. I booked the following on Finnair.com
TPE-NRT-HEL-RIX | RIX-HEL-ICN-TPE

The night before my return leg, I receive an Email from Finnair stating that one of my flights has been changed. I was bumped off CI161 for the ICN-TPE portion of my flight and booked on CI163, over 8 hours later. The Finnair app said that if I don't agree with the change, to (click below) and see options. There were no options.

When we checked in in RIX, the agent said they could not help us and to check with FINNAIR staff in HEL. Upon arrival in HEL, Finnair staff told us that they see that CI has changed the flight, but they were unable to do anything, because it was a request from CI. We should check with CI in ICN.

After arriving in ICN, we went to the gate and our original flight (CI161) has not yet started boarding. The flight was not cancelled. We were just bumped for no reason.We asked CI why we were bumped and they said to call FINNAIR, as they have no way to change the booking. CI agents said "it's not our problem. Talk to Finnair" and would not even as much as give us a coffee in ICN airport for our 9 hour layover. I spend the next several hours on the phone with FinnAir and China Airlines, with each saying it's not their problem, talk to the other. CI agents eventually said that even though we got to the gate before CI 161 started boarding, ICN airport has a minimum connection time of 90 minutes. Our flights were 75 min apart. CI kept saying they can't help us and if we want any reimbursement at all, that is 100% on Finnair.

We arrived in TPE 9 hours after out planned arrival, and trains had stopped running. Total travel time was close to 30 hours! I had to pay for a private taxi 140km home and arrived home at 1:30am. I had to cancel my work commitments the next morning.

I Emailed both China Airlines and filed a claim with FinnAir on their website.

China Airlines official final reply on this case:
"Dear passenger,
Thank you for contacting China airlines.
Please accept my sincere apologies for the delayed response. Your patience is well appreciated.
We are very sorry to hear about your situation.
Upon checking the case, your ticket was issued by FINNAIR if you have any problem still need to contact with them.
Please contact FINNAIR and their staff will assist you with your claim.
Very Truly Yours,
China Airlines Customer Service"

I just received official final reply from Finnair. "Thank you for contacting Finnair Customer Relations and for taking the time to share your feedback and experience with us.

Kindly note that even if you have booked directly with Finnair, one or more of your flights may be operated by another airline. In this case, your flight was operated by China Airline , hence, we kindly request you to contact the operating airline to claim about the canceled flight and possible reimbursement of your additional expenses.

Allow me to inform you that EC Regulation 261 solely applies to operating carriers. Pursuant to article 3(3), the operating carrier is always responsible for the obligations under the Regulation and not, for example, another air carrier that may have sold the ticket. The notion of the air carrier is presented in recital 7.

I hope your future flights go according to plan and that you have a positive experience in every way.

Kind regards,

Finnair Customer Relations"

Who is responsible in this case and who can I talk to next? I know EU has rules about this, but they do not cover flight segments which originate outside of the EU.
Both airlines are just telling me to get lost. I'll walk before I ever fly these airlines again.
Help?

I should also add that China Airlines refused to upgrade my partner on the delayed flight (CI 163) and instead stuck us in in E&F, middle seats in the back of the plane.
They said they could not upgrade because the flight bumping was because of FinnAir and the flight was full.

I neglected to mention that the flight was operated by FinnAir with the exception of the TPE-NRT and ICN-TPE segments (operated by China Airlines) - but purchased from FinnAir.

After spending a lot more time on the phone with FinnAir, they have confirmed that CHINA AIRLINES cancelled my flight. the flight itself was not cancelled, as we arrived at the gate and were denied boarding, being told the flight was full. Not even offered a coffee for the 9 hour wait, compensation for the 140km taxi ride home, any acceptance of responsibility and were just told "it's not our problem".
What can I do after China Airlines told me to get lost?