how did you create this "new My Bitcoin wallet" which you transferred your bitcoins to? and when did you do the transfer?
blockchain.info is known to have bugs and their BCH wallet is new so there may be some issues.
if you transferred your bitcoin after the fork then your BCH is still in your old keys and if you transferred it before, then BCH is in the new keys. as long as you have the keys you have both BCH and BTC.
my guess is that when they imported your wallet into BCH wallet, they did it only for one wallet and not the other (the new My Bitcoin Wallet that you created).
contact support and ask them for help but first check your BCH balance here:
https://bitcoincash.blockexplorer.com/ to make sure you really have them.