Well, please check your ticket and you will see what happened ;-)
Now let me explain what happened here that everybody who's in the same situation may find some piece! What Twobitcoins did was to sent BTC from one Mt.Gox Wallet to another Mt.Gox wallet, in this very case all transactions are instantly confirmed and done without going through the blockchain.
Yes, thank you for the response (both on the help desk and here).
It is an understandable policy, but it can also result in confusion when using a withdrawal to pay someone that you don't know is using Mt. Gox. You might consider providing some indication that a withdrawal was processed internally, e.g. on the withdrawal confirmation page and the transaction history.
Even that may not be enough for some use cases, like if a third party is supposed to confirm that a transaction took place by looking at the block chain. But I understand the desire to avoid unnecessary transactions, so the tradeoff may be acceptable.
Yeah, that's really bad. When you click withdraw bitcoins it's clear that you are asking for a transaction to be written to the block chain. That's your proof of payment ffs.
There is even a separate option for sending MtGox BTC credits, if people want to save MtGox the hassle of actually making the transaction they can use that.