Make sure you put in a support ticket.

The same thing happened to me on Cryptsy.  This was their response:

"I am really sorry for any inconvenience this may have cause you. However, we are seeing a delay when it comes to processing CLAM transactions. Our technical support team is aware of this issue and they are working on a fix. Please know that you have the option to cancel these transactions to return the coins back to your balance if you like. Just kindly let me know by responding to this ticket so I can process it for you. We greatly appreciate your understanding and patience."

After this happened 3 times, I finally transferred everything out.  I was wondering if they were holding the CLAMs for staking.  Very Odd.