you probably have the same bug that numerous vault owners have been affect by since the last patch. you have an objective to survice a molerat attack but it's bugged your vault because there was a molerat attack in an empty room. Now your game immediately crashes after the game starts to load. Thank you for posting, the more people post maybe we'll get heard. Gonna be tough, since their other games have way more posts in their forum, we are small compared to their other games.
Hey friend, our vaults have all suffered the same fate. I'm on day 19 with absolutely no help from Bethesda. Get your money back, you deserve it. Nobody should treat customers like this. I made 4 purchases, and requested refunds on all of them directly from Apple. 2 were refunded immediately, the other 2 were refunded a few days later. Here's the site info:
reportaproblem.apple.com
Sign in, click on the purchases you made, and request a refund.