Hello AA/VV,
First of all, I would like to know if you´ve sent your CV to Iberia Express in Spanish, English or Italian. That´s because you should have done it in Spanish. If you didn´t do it like that, try again 🙂
There are people from Venezuela, Russia, Polonia… working for Iberia Express, so I´m quite sure your nationality is not a problem.
On the other side, your Italian Certificate is signed by AESA, right? Same than ours. That´s the way all European Cabin Crew Certificates are signed nowadays.
Just try it again. I know you have good English, so by patient and good luck 🙂
Best wishes.