If the airline is to blame and has not informed you of the cancellation at least 14 days before departure, China Airlines Cancellation Policy EU law states that you can receive up to 600€ for the problem. The exact amount depends on the length of your trip.
Claim Compass can help the airline collect money owed to you. Just enter your flight details into our rewards calculator and we'll take care of the whole thing.

https://www.cancelation-policy.com/china-airlines-cancellation-policy