The addresses you sent funds to/from?

Bitcoin diamond have Replay protection I believe so It's possible that the wallet you were using malicious code, assuming that you claimed your BCD using that wallet with your BTC seed/private keys.

ow that's a mistake, how much bitcoin you lost?
I think better to save your back up file or private key (if own wallet)

Sounds like its time....to buy more bitcoin!!

Sorry for your loss...

The shitposting to knowledge ratio on this forum is quite low. The redditors might be better to ask...

Does this help?

https://www.reddit.com/r/BitcoinDiamond/comments/8girme/help_please_help_my_btc_was_stolen_from_diamond/

"I just had the same problem - I entered currently used seeds. I used the bitcoin diamond electrum wallet. I was able to recover bitcoin diamond from my Coinomi wallet. I was not able to recover bitcoin diamond from my Trezor. However, I later noticed that an amount of bitcoin corresponding to the amount of bitcoin diamond I received from my Coinomi wallet had been moved. I checked my Trezor and saw that all of the bitcoin had been moved. I'm hoping that my bitcoin was not hacked and somebody has a solution! "

A key question for you, from where you download Electrum BCD, is it maybe from electrumdiamond. org? This is fake wallet, read more about that in this thread. Only legit wallets for this coin is on official site https://btcd.io , and there is also Electrum BCD.

I do not understand why people risk BTC to claim some low value fork coin which currently worth a little more then 1$? But even if you do that, first thing to prevent such situation is to move BTC to completely new address/seed (creating new wallet), and then play with old private keys/seed.

Did you read any safety tutorials first before importing your private keys/seed to any compatible wallet of bitcoindiamond?

Its always recommended that you have to move your bitcoin funds to get any fork coins on your wallet (if there is) before importing it to any fork wallets for the safety of your funds, if you imported your keys/seed to any fake wallet with still funds on it then so be it, your BTCD with your BTC is lost forever. And besides compatible wallets are listed on their site which is the most recommended one.

It seems like no one can give you ideas. What happens to you right now is the carelessness of yourself because you are not aware of your data. Maybe some people have good advice to tell you not to do this again. But not by returning all your BTC.

You can contact their support team, each wallet has their own support team and I think that they can (hopefully) regain your BTCD back, I just hope you'll be able to get it back, and next time be sure to read more, and be cautious, there are a lot of thieves out here in the web, be cautious and make sure that what you are doing is correct, because some decisions cannot be undone. Goodluck!

Your coins are most likely gone,, but there is a  chance the exchange will return the coins to you.  I've heard of many people sending bch to btc addresses to exchanges and not receiving a refund.  You have to be extremely careful when sending large crypto transactions.  Always double check what your doing and make sure the address is correct.