Same with me...
Got a response from support saying: "We are still fixing a few issues with the API. The funds are not lost. They will either get to the destination or be returned. Please wait for a bit. Sorry about the inconvenience."
Key part of that being "or be returned". If funds are returned to the customer I'll not be especially happy, considering some emailed rather angrily, forcing my hand into processing their orders.
Check the receiving address on blockexplorer.com, which should be clear of any of blockchain.info's database issues. If your transaction is not there, then it was probably never transmitted to the network by blockchain.info.
If that's the case, download your backup file, import the private keys into MultiBit sweep them to a new address, and after that is confirmed, resend the transaction. If blockchain.info gets the transaction unstuck, it will be rejected by the network as a double-spend, if all the old addresses are empty.
