It would help if you said when else he gets you with 360s. If you're dropping combos and he's getting you that way, learn/practice some actual combos. If you're getting hit out of blockstrings vary it up/jump. If you're getting hit mashing Inferno Divider on wakeup, stop doing it. "Stop sucking" is kind of blunt but honestly it's the best way to sum this up. 360 mashing only works on people who suck. Watch videos of your matchups, learn what they can do, learn what YOU can do, and get better.
If it's just GH he gets you on... stop doing it (as much/in the same situations you keep doing them)? Sorry, not a Ragna expert. But in any case you would have been better off asking in the Ragna section. And not in its own thread.