Piggy bank keeps “disappearing”, along with all earned bars

With the Piggy Bank you can buy boosters at a reduced price, but there are often cheaper and better deals if you want to buy boosters. Keep playing, collecting boosters through the events. Then you have the freedom to decide whether and when you want to buy something.

@lstroud2 The piggy bank has to be bought and it will only give you a certain amount of time to purchase these gold bars at the reduced rate. The piggy bank feature has always worked this way and can come and go in your game. You are not always guarenteed to have the feature