Lost our purchase – Transformers Rescue Bots: Dash Review

My son really likes this game. I let him spend his allowance to unlock the full cast of characters, for $10. A couple of weeks later he asked me if he could unlock them "again", and sure enough they had been relocked. I don't understand why this happened and so I won't let him buy them again, which limits the game and makes him sad. Why would in-app purchases already made disappear?
Review by Bjuneky on Transformers Rescue Bots: Dash.