Considering how finicky CVT's can be, and how expensive they are to replaced, I would follow the manufacturer recommended service intervals and fluid types. From what I've read, most manufacturers recommend changing CVT fluid every 30k miles or 24 months. You should double check with your owners manual or dealership service department for the correct fluid type and service interval.
I would also recommend having it done at an independent mechanic who is experience with CVT transmissions, rather than the dealership (expensive) or a quick-lube type shop (incompetent, in my experience).
The amount of time I have spent searching for this information would be described by the guy that signs by paychecks as "clear out your desk, and don't bother coming in on Monday."
I was able to find some information by searching for the Mazda Demio, which is the 2's JDM (Japanese Domestic Market) model name. Even then, I was only able to find the recommended fluid is CVTF 3320, which is produced my multiple companies (Mobil 1, Valvoline, etc).
Considering that the dealership is not willing to help, I would call the Mazda corporate office, who should be able to look it up, or connect you with someone who will be able to answer your question.