i made 6 purchases for equipment, no Opal was purchased. But still got "Invalid data(6)", how often should i do the purchase? like 5/hour or 5/day or like wait 5 mins between 'em?...
I used to play this game a lot. Yeah, the actual purpose of the free purchase was only for character unlocks since it's not easily detected. Any other in-app purchase would be detected at some point(could be instant or days) when you enter secured areas like PvP or events, even normal stages can detect DMG numbers. The devs are active in hunting hackers in this game so they'll notice even the smallest changes in your account.