Hi, How did you get it back. I have a similar problem. your help will be highly appreciated.
If you sent BCH to a BTC wallet, and you have access to the private keys for the BTC wallet, you will be able to retrieve your BCH by importing the private keys into a BCH wallet.
If you sent BCH to a BTC wallet, and you DO NOT have access to the private keys for the BTC wallet (ie. an Exchange wallet) you will need to get assistance from whomever controls that wallet (ie. The Exchange) to retrieve the BTC for you.