HI all,
I have a question here.
I bought my Vita during my japan trip and i bought Accel world Vs Sword Art Online in japanese version as well.
But i didnt know that to unlock the infinite dungeon, i need to purchase the Japanese version DLC.
I have a Malaysian PSN and i started the game with Malaysia PSN.
So i went to japanese ps store on PC and I saw the DLC that i want. I purchased it. I followed the guide from google (asked me to format my PSV then log in to JP PSN ACC. I did so. But when i put in my memory card, they asked me to format my memory card. I tried to dl the DLC that i purchased but it shows NW error. But i have no wif error. I even tried to start the game but it shows that i couldn’t start my game with JP psn because of my memory card
Is there any way I can remain my game data and how do I download my JP DLC?

Sorry for my bad english.

You can’t.
Vita only allow a single account to be used at any one time.
Unlike PS4 which has primary account, and you can play games/DLC from that account, you cannot do that for the vita.

If you’ve not launch the dlc. I suggest you ask for a refund.