I booked a ticket on international route with multiple stops (Stockholm-Brussels-Abu Dhabi-Mumbai). Stockholm to Brussels was with Brussels Airlines and the rest of the trip was with Etihad, but on a single ticket.
The flight to Brussels was cancelled by Brussels Airlines due to bad weather conditions at Brussels airport. The BA ticket counter at Stockholm airport rebooked me on a later flight. The ticket that was given to me said that my reservation is confirmed all the way. But when I reached AUH airport, Etihad people told me that flight to Mumbai is not confirmed (even though the ticket given to me by Brussels Airlines said it was confirmed). They denied me boarding and gave me a boarding pass for a flight that was taking off 9 hours after my original flight. They also refused to give me any kind of accommodation or meal vouchers because they said that it was the fault of Brussels Airlines for giving me an unconfirmed ticket.
I contacted BA customer support but they said that the ticket was confirmed and it is Etihad's fault for denying me boarding. Both companies have denied my compensation claim for denied boarding. What are my options now?
Edit: After two months, I got an email from Brussels Airlines and this is what they said: when they gave me the ticket, as per their system, the booking was perfectly fine and confirmed. But something went wrong while the ticket was transferred from BA system to Etihad system, and in Etihad's system, the ticket was not confirmed. And since this situation is "beyond their control", they cannot provide me compensation. But just as a gesture of goodwill, they will pay me 200 euros for the inconvenience caused. Should I accept their offer or press for full compensation (550 euros)?