I'm really sorry to be the bearer of bad news, but this casino has had scam accusations and I haven't seen any cases having a happy ending in which the person who is accusing got what they wanted, that's why my advice to you: take your 1000$ and withdraw from that casino, you will not be able to get what you are complaining about, simply withdraw your 1000$ and forget about it, you can see this case:
I won't say I don't see any happy ending. You can check this thread
Duckdice.io paid me the full amount, I have no complaints, thanks!. This is very recent case and the user get paid in full.
I received the money today in full, thanks a lot to the team Duckdice and separately @Kirito89
I would suggest OP to contact
Kirito89 or
bobstone as they are working for duckdice as a support agent and they are pretty much active on the forum.