In the Block Activated I would add a test account, run it, then comment it out. Then I would get the account and I could get it fine. Once I restart the world and try to get the account again it would be empty. The set Account statement I used is commented out here: https://github.com/BeardlessBrady/Currency-Mod/blob/master-1.11/src/main/java/gunn/modcurrency/mod/block/BlockATM.java#L70