I've booked a flight LYS -> FRA -> EZE -> USH on Lufthansa website. The first two flights are operated by Lufthansa, so I was able to call their customer service and add a bicycle on my ticket. The last leg is operated by Aerolineas Argentinas, and the Lufthansa's customer service told me to contact them to add the bicycle.
On Aerolinas Argentineas website they give a phone number for "international calls outside Argentina"; as I don't speak spanish, I guess I'd need that. But it doesn't work.
How can I tell Aerolineas Argentinas that I will have a bike with me?
EDIT: I can't use the contact form on their website as it asks for a booking number. My booking number is from Lufthansa and is not valid for Aerolinas.