Bought worlds lost and markedplace crash

About 3 weeks ago all the worlds my sons bought were locked and they were asked to buy them again to gain access. when I access markedplace and presses the "worlds" (verdner) button the app crash. In the bought packaged I can only see two worlds despite buys of more than 20 different worlds during the last year. 

Logging into the account on a different Ipad reveals that no coins are to be seen and all worlds are gone