You didn't make no mistakes. You've have been programatically decieved to give approval for your token to be stolen. That's how it is here on web3.

HELP! I’m a newbie and yesterday I wanted to buy #Dsync on web3. I mistakenly transferred around 460$ of my crypto straight to the DSYNC account instead of swapping them. Result, my crypto gone and no DSYNC coins in my wallet. I have emailed #destranetwork to explain the situation and asked how to receive the coins I have ordered. So far they haven’t responded. Also the support options here on #Binance app lead to a death end. All advice and suggestions towards my problem are super welcome, thanks!