air travel – Flight Changed Itinerary by full day, Ticket bought through 3rd Party

Similar to: Flight itinerary/time/date change

I had scheduled a flight (Air Serbia), and purchased it through a 3rd party company (Orbitz).

After the hassle-free 24 hour cancellation period had past, I got an email telling me the flight had been pushed back an entire day. This won’t work for me since I have connecting plans at the destination and don’t want to cancel a number of things.

The flight is between to EU countries, but Serbia itself is not a EU country, so I am not sure if/how the EU Air Passenger rights apply.

I am looking to get a full refund and buying another ticket, but every time I get through to the third-party company, they tell me they don’t have a prior agreement and all they can do is reach out to Air Serbia asking for a refund. They tell me it will take X time, and I will get an updated status email when it is confirmed. I have done this twice, waiting longer than X time, to no response.

Am I entitled to a full refund (given its an EU flight)? If so, am I supposed to go through the third-party I bought it from, or do I need to go directly to the airline?