We're sorry that this has happened. Usually, it shouldn't be possible as all purchases are associated with the account that bought them but if it has, we can help.
If you were using two different accounts, you could ask for a refund on one of them.
If you bought an individual app and also bought a bundle that the app is in, please contact us with details and we will try to work with you to sort something out.
If you're not quite sure what has happened, or for any other reason, please contact us with as much information as possible and we will help.