About Phantasy Star Portable 2 - equipping units?

[vsub_]

For example if I let LV55 "Vanda Orga"(earth element)hit me with his fire throwing or fire breath attacks 4 or 5 times,I'm dead and they are usually in groups and they do the same thing.

I also tried letting him to hit me but both armors and there is almost no difference in the damage I receive

Rabol Solid (A Class)
51% Earth
DEF 231
EVA 121
MND 115

Rabol Opad (S Class)
24% Fire
DEF 316
EVA 166
MND 158