Update:
Dekado isn't a wallet, it's a spamming ponzi scam.i am new to this bitcoin. say about a week. i dont know what is private key or where it is available and how to use it. please guide me the process
Sorry to inform you: your money is gone. Even if you wouldn't have sent it to the wrong chain, it would have been stolen anyway.
If you're new to Bitcoin, why would you send your newly bought money to just any site that promises some lie?
General note: don't send many to ponzi scammers! They earn millions from scamming users, and they'll just move their "business" to the next site.