Procedures are pretty straight forward.
You send the amount you wish to be swapped to the OTC Address.
The OTC Address sends back the amount -2% of the token you wish to acquire.
If you don't trust Binance Pay or Binance in general, I can't deal with you and I repeat I'M NOT A PAYMASTER, I DONT TOUCH YOUR MONEY.
So Binance will guarantee that you will not get away with other's money and that you will send the funds after you get others? And since you say that you don't touch the money, does this mean that you are talking about a bot? Because in the conversation above, you talk like you will make the transaction.
Sorry, but I'm a bit lost here...