A bit of context to the question: I took a flight this Saturday with Iberia and my checked-in baggage was lost. I had all my clothes there so I had to buy some and according to the Passenger Rights I'm allowed to ask for a refund. They gave me my bag today.
I would normally ask for the refund in person and file a complain in the same airport but the company told me that I can just do it via phone or their web page.
I had to do it via the web page because I couldn't call today but I was wondering if any of this ways is more effective than the other in terms of getting a quick response from the airline and achieving the refund without much trouble.
I ask this because lately I've had to fill a few complaints against Iberia and some times they were solved very quickly and some others were much more difficult to resolve.
How can I maximize my chances of getting a quick reply and succeeding with my complaint?