And it is not credited back into my account.Where did it go? Can I get those coins back?
When a transaction has disappeared from the unconfirmed mempool, the transaction is "cancelled".
Blockchain.info is a service, is a service, is a service, is a service and - repeat with me -
not the blockchain[1]. Whatever they claim about a transaction may or may not have anything to do with the rest of the network. More often than not the information they display is in contrast to the rest of the network and I would always check with at least one different blockchain explorer.
->
https://www.blocktrail.com/BTC/tx/33d7f0de4826a24d18fcc81e799960812df3e47d104f6ef66534249b240605ceThe TX was in double spend a day after it was issued ->
https://www.blocktrail.com/BTC/tx/a0527492e033153e823b99577e0bcc6a58d9111771916fae0c8fefa90e0a4b05which caused it to be "cancelled".
So the coins has never left your address/wallet.
Since the double spend TX has >1700 confirmations I think we are safe to say that the coins left OPs wallet.
Your wallet client still thinks the transaction is pending confirmation and deduced the sent coins from your balance. What you need to tell your client to "forget" the transaction and refresh the balance.
Which wallet/client do you use?
Good question.
[1] Sorry for know it all post, but if you rely on bc.i you will eventually make bad decision because you have incomplete information.