Where can I spend Okica card balance?

I was a dumb dumb and put 5k Yen onto my Okica, thinking I'd spend 4k on the busses to and from Churaumi Aquarium. Turns out that they do accept IC cards — but only Pasmo or Suica, and not Okica.

So now I'm stuck with more yen on my card than I can reasonably spend within the 30ish hours that I'm still on Okinawa. Is there some other place I can spend the balance? I tried paying for my onigiri at Lawson's with it, but they told me no :') Does some other convenience store accept it?

Thank you!