I can think of two things that may have happened:

1. The website you visited wasn't Binance.
2. You have a bitcoin address clipboard malware that changes the address that you have in your clipboard to the hacker's address.

Did you double check the address you pasted before sending the coins?
Can you run a malware scan to see if your computer is infected?
Can you check your browser history to see if you clicked in any fake Binance website?