I just noticed that if you want to fetch a transaction which is failed for some reason (lets say: [40100] Problem with credit card data.) then the php lib throws an \Paymill\Services\PaymillException instead of returning the transaction. I don't see why it is necessary in this case, as the action was successful (fetch an information about a payment transaction) and only the transaction itself failed. I think in this case the api should return the transaction object instead throwing an exception.