I am not pointing my finger to you or OP, I am trying to clarify things, for the IP shared by three users, I believe OP said that his wife also played, so probably the other one is his wife's, and the third one is... OP, can you shed us some light here? Meanwhile, CallMeJojo does your platform specifically prohibit multiple user from the same address?
"Wife" could be anyone else though 
How about the third account, it's it his son or uncle?
So they all realized the site was buggy and they decided to exploit it at once?