When it does work (seemingly random and the balance always shows 0), nostr:npub1dx5q2el8nd4eh3eg9t2e25fd7zuqg7zxz6ldkc3uzgh66ss2yc6st288sj tells me every time that they’ve already been claimed.

Just emailed the author or Nostore about this. Hopefully, he’ll jump back in. I’m aware of no other option for mobile Safari.