Same problem here. Bought two packs and did not receive them, tried contacting the developer, but they redirected to google play support for a refund. Instead of just recieving the items.
Contacted googgle play support and recieved refunds for my purchases. it's quite easy to get a refund if you have not recieved the items.
tried a couple a times to buy a large pack of lunchboxes but each time it failed. when returning to game the game restarted.
when buying one pack the purchase succeeded.
have been testing some more.
and it seems if you take too long to purchase an item the game restarts, just like when you go to do something else on your phone and then return to the fallout shelter, and your purchase is not registered.
what helps is if you don't have to reenter your password each time.
but gamesas should fix this.